From . . . the general endeavour to attain a relative superiority, there follows another endeavour which must consequently be just as general in its nature: this is the surprise of the enemy. It lies more or less at the foundation of all undertakings, for without it the preponderance at the decisive point is not properly conceivable.
CLAUSEWITZ, On War
Chapter VI
The Anzio BeachheadItalian Lands vs. German Blood
As the Allied force used its strong right arm to punch its way from the southern front toward the Hitler Line, the left arm, which for several weeks had been gathering strength within the confines of the Anzio beachhead, remained flexed for a sharp hook against General Mackensen's Fourteenth Army, keeping vigil over the beachhead. In accord with General Alexander's order of 5 May, the attack from the beachhead was to be launched on 24-hours' notice at any time after D plus 4. The Allied armies commander had reserved for himself the final decision as to the exact time.1 It was to constitute the hoped-for fulfillment of Alexander's--as well as Churchill's--original strategic concept behind Operations DIADEM and SHINGLE, a one-two punch designed trap and annihilate a large portion of Kesselring's armies south of Rome before moving in to capture the capital of Mussolini's crumbling empire. This strategy rested upon the premise that it was more profitable to destroy enemy units than to take ground. It would not be enough merely to push back enemy armies but to wipe them out to such an extent that they would have to be replaced from other theaters to avoid a rout. Yet the lure of Rome for all Allied commanders in Italy threatened to undermine that premise.2
This strategy had yet to receive full acceptance within the Fifth Army, although the original mission in Operation SHINGLE had included a thrust from the beachhead to cut the XVI Panzer Corps' line of communications.3 As far as General Clark was concerned, the question of which direction Truscott's corps was to take once it had broken out of the beachhead had yet to be answered. In any case, since it was a corps within Clark's army that was involved, Clark intended the decision to be his, not Alexander's.
The question of the timing of the breakout offensive depended to a certain extent upon its direction; thus timing remained a subject of controversy and some confusion until the very eve of the offensive, although the formal order from Headquarters, AAI, on 5 May had clearly stated, as noted earlier, that the decision on timing was to be Alexander's.
The question of which direction the offensive was to take following the breakout had been a matter of controversy
within Allied planning circles ever since January 1944, when the Allies had first come ashore at Anzio. The controversy had polarized about the persons of Alexander and Clark and stemmed largely from differing views on the role of the Anzio beachhead. From its very inception Clark had opposed the very concept of Anzio and during the planning stage had recommended dropping it. This view was also held by U.S. Army Chief of Staff General George C. Marshall. Thus Anzio was a British project, although carried out in large part by Americans. This anomaly may have had something to do with the later disagreement between Clark and Alexander.4
General Alexander originally had envisioned the beachhead as a base for a thrust northwest along the axis of Highway 7 into the Alban Hills, while the main Allied forces drove the enemy from the southern front up the Liri valley into a trap formed by the VI Corps athwart the enemy's line of communications in the Rome area. In developing plans to implement that concept early in 1944, General Clark had reversed the roles of the participating forces. He was then convinced that the VI Corps should be limited to pinning down the German Fourteenth Army opposite the beachhead, thereby preventing Kesselring from shifting reinforcements southward to assist the Tenth Army, which was then opposing the Fifth Army's attempt to break into the Liri valley.5
Throughout the winter of 1943-1944 the matter had been allowed to simmer quietly, but with the coming of spring and revival of plans for a May offensive, the controversy had boiled again. Although Alexander had shifted his attention from the Alban Hills and Rome southeastward some twenty miles to Valmontone and Highway 6, his original concept--trapping a major part of Vietinghoff's Tenth Army between a blocking force striking out from the beachhead and the main force advancing from the southeast--remained unaltered.
On the other hand, the Fifth Army commander's views had changed significantly. In April, after Alexander had regrouped the two Allied armies, General Leese's Eighth Army rather than General Clark's Fifth stood before the entrance to the Liri valley, leading Clark to wonder whether the British rather than the Americans might reach Rome first. The U.S. VI Corps, therefore, seemed to offer Clark a chance to counter this geographical advantage in a race for the Italian capital. If Truscott's VI Corps could break out of the beachhead and strike directly northward into the Alban Hills, the Americans might win that race. Moreover, in addition to winning the race Clark was very much concerned about reaching Rome before the beginning of OVERLORD, as George Marshall had frequently and pointedly urged him to do.
General Clark, no longer considering the beachhead a holding action as he had during the winter, saw Truscott's corps as the potential spearhead of a Fifth Army drive on Rome. The Alban Hills had become in Clark's eyes a gateway rather than a barrier to Rome.
Moreover, as long as the enemy held the hills in strength a threat remained to the flank of any thrust from the beachhead in the direction of Valmontone and Highway 6. Clark believed that his forces should secure the Alban Hills before attempting to cut off the Tenth Army's right wing at Valmontone.6
General Clark, just as he had earlier modified Alexander's directive for the offensive along the southern front, now laid the groundwork for another, even more important unilateral change, this time in Alexander's guidelines for the VI Corps' breakout offensive from the Anzio beachhead. Clark directed Truscott to prepare a plan for an offensive to be launched on forty-eight hours' notice along one of four possible axes: northwestward along the coastal corridor, across the Alban Hills directly toward Rome, northwestward through Cisterna to Valmontone on Highway 6, or eastward to Sezze in the Lepini Mountains, overlooking the beachhead from that direction. On 2 April, during a conference with his army commanders, General Alexander had opted for an attack toward Valmontone in the hope of cutting the enemy's line of communications with the main front. Yet Clark's instructions to Truscott had carefully avoided specifying a choice among the possible axes of attack from the beachhead, for General Clark failed to share the belief that significant numbers of Germans would be cut off by a thrust to Valmontone and Highway 6. There were, in Clark's opinion, just too many alternate routes of escape available to the Germans. Alexander's desire for the thrust on Valmontone had, in Clark's view, been dictated mainly by an expectation that it would help to loosen up German resistance opposite the Eighth Army and enable the latter to accelerate its advance up the Liri-Sacco valley. For Clark that was insufficient to justify the risks to his Fifth Army inherent in Alexander's plan.7
On 5 May Alexander visited the VI Corps headquarters where Truscott laid before him the four alternate plans which the corps staff, as directed by Clark, had developed during the two preceding months. The plans went by the code names of GRASSHOPPER, BUFFALO, TURTLE, and CRAWDAD.
GRASSHOPPER outlined an attack toward the east in the direction of Littoria-Sezze with the object of making contact with the Fifth Army's main force advancing northwestward. Only if troops on the southern front appeared to be bogged down and in need of help to achieve a junction with the beachhead was GRASSHOPPER to be mounted. Operation BUFFALO, which most closely corresponded to SHINGLE's and DIADEM's original strategic concepts, called for a thrust northeastward through Cisterna, Cori, and Artena to Valmontone. Its objective was to block Highway 6 and thereby cut off the retreat of the Tenth Army's right wing. The destruction of a significant part of the Tenth Army would open the road to Rome along Highway 6. Operation TURTLE called for an attack astride the Via Anziate (the Anzio-Rome road) and the Rome railroad, northward through Carroceto and Campoleone to a junction with Highway 7
GENERAL TRUSCOTTabout a mile south of Lake Albano in the Alban Hills. Operation CRAWDAD outlined a drive through Ardea, twelve miles northwest of Anzio, roughly paralleling the coast southwest of the Alban Hills. In terms of distance, CRAWDAD afforded the shortest route to Rome, but the road network was less favorable than that offered by Highway 7. After looking over the four plans, General Alexander quickly dismissed all but BUFFALO. The drive on Valmontone, he declared, was the only operation likely to produce "worthwhile results."8
While BUFFALO was eminently suited to Alexander's strategic concept, it conflicted sharply with the idea taking shape in Clark's mind. The Fifth Army commander had no faith in the plan. When Truscott informed him of Alexander's visit and of his comments on the breakout plans, Clark immediately telephoned the Allied commander to express irritation over what he interpreted as an unwarranted interference with the Fifth Army's command channels.9 Clark insisted that he wanted to keep his own plans flexible and not be tied to "pre-conceived ideas as to what exactly was to be done." Rejecting Alexander's apparent assumption that Operation BUFFALO would trap a large part of the German Tenth Army, Clark added that he did not "believe we have too many chances to do that--the Boche is too smart." Clark agreed that Truscott should give BUFFALO first priority in his operational planning, but he insisted that the VI Corps commander should be free to continue to develop other plans as well. The Fifth Army commander declared with some logic that he had to be "prepared to meet any eventuality" and keep his "mind free of any commitment before the battle started."10
Even before these exchanges Clark had become suspicious that there might be "interests brewing for the Eighth Army to take Rome." But as he was to note later, "We not only wanted the honor of capturing Rome, but we felt that we more than deserved it. . . My own feeling was that nothing was going to stop us on our push toward the Italian capital. Not only did we intend to become the first army in fifteen centuries to seize Rome from the south, but we intended to see that the people back home knew that it was the Fifth
Army that did the job and knew the price that had been paid for it." These considerations were for Clark "important to an understanding of the behind-the-scenes differences of opinion that occurred in this period. Such controversies, he observed years later, were conceived in good faith as a result of honest differences of opinions about the best way to do the job.11 Alexander, however annoyed he may have been, generally kept his feelings to himself. Not only did he not reproach Clark in his dispatches but even failed to mention their disagreement. Such was the character of the Allied armies' commander.12
German Plans
Fundamental differences over strategy between Alexander and Clark concerning the direction the VI Corps' offensive was to take had a counterpart within the German command where opposing concepts, especially between Kesselring and Mackensen, the Fourteenth Army commander, exacerbated relations between the two men. Field Marshal Kesselring believed that the Allied forces on the beachhead would attempt to break out in the direction of Valmontone in an effort to cut Highway 6 and sever the line of communications to the southern front. General von Mackensen, for his part, believed that once free of the beachhead, the VI Corps would advance into the Alban Hills along the axis of Highway 7, next to the coastal road, the most direct road to Rome.13 Thus did the Fourteenth Army commander anticipate the strategy even then taking form in Clark's mind.
This disagreement between the army group and Fourteenth Army commanders was further complicated by Hitler's intervention in the development of strategic and tactical plans in Italy, about which he was deeply concerned even though far from the front, and even though Italy was a secondary theater. Anticipating the time when the Allies would attempt to break out of the Anzio beachhead, Hitler as early as mid-March, had instructed Kesselring to study the possibility of employing the so-called false front tactic, which, Hitler recalled, the French and Germans had successfully used near Rheims in the last year of World War I. More recently, the U.S. VI Corps had used it in repelling German counterattacks at Anzio in mid-February. This tactic may be described as follows: just before attacking forces began their preparatory artillery fire, the defenders would evacuate the forward positions for previously prepared positions in the rear of the main line of resistance. After the offensive had spent itself and the attackers were thrown off balance, the defenders' reserves, waiting securely in the rear, were to counterattack and destroy the foe.
On 1 April Kesselring responded to Hitler's instructions with a plan of his own. He had already directed Mackensen, he said, to begin an extensive thinning of the Fourteenth Army's forward battle positions and to dispose his defenses in greater depth. Forward positions
were to be held in strength sufficient only to compel the Allied forces to attack with all their heavy weapons. While the Allied attack wore itself out against numerous strongpoints arranged in depth throughout the main battle position, German losses would be held to a minimum. Even if the Allied forces penetrated the main line of resistance, there would still be time, Kesselring believed, to bring up his reserves for a counterattack.
Taking a mildly critical view of Hitler's tactical suggestions, Kesselring pointed out an inherent weakness. How could one determine early enough that a given Allied artillery bombardment presaged an offensive so that forward positions might be evacuated in time? To delay too long risked having those positions overrun and thereby exposing the main defenses; yet a premature withdrawal could mean loss of the entire main line of resistance. Moreover, Kesselring argued, it would be difficult to deceive the Allies for any length of time as to the real location of the main line of resistance.
Hitler, too, was concerned about the possibility that Mackensen's secondary defenses might be destroyed by artillery when the Allied attack rolled over his forward positions. When the Fourteenth Army's chief of staff, Generalmajor Wolf-Ruediger Hauser, visited the Fuehrer's headquarters early in April, Hitler indicated that he wanted Mackensen to consider shifting his secondary position even farther to the rear.
As finally drawn, Kesselring's defense plan represented a compromise with Hitler's concepts. It called for temporary evacuation of the forward areas and occupying previously prepared blocking positions as soon as preparations for a full-scale Allied attack were identified, but only near the strongpoints of Aprilia (called "the Factory"), Cisterna, and Littoria, in the northern, central, and southern sectors, respectively. Defenders elsewhere were to hold in place.
Although the Germans at first believed that waterlogged terrain would limit large-scale employment of armor in the beachhead until well into the spring of 1944, by March they had begun to suspect that another breakout offensive by the Allied forces would not be long in coming. As the ground began to dry out toward the end of April, expectations increased.
Early in April the Fourteenth Army commander reported a significant increase in Allied artillery registration fires and frequent use of smoke over the port of Anzio and other Allied debarkation points. Anticipating that the activity possibly foreshadowed the expected offensive from the beachhead, Kesselring ordered the planned withdrawal, but when April passed with no such attack, he concluded that the Allied offensive would begin not in the beachhead but either on the southern front or possibly with another amphibious landing. He therefore ordered the Fourteenth Army's troops back to their original positions.
The Terrain
The Anzio beachhead sprawled over a large coastal plain which in Roman times had been a fertile farming region, but which through the centuries had become a vast malarial swamp. Reclaiming this pestilential region, known as the Pontine Marshes, had long been a
dream of Italian agronomists. In the decade immediately preceding the war much of the area had been partially drained and had become one of the agricultural show places of Mussolini's government.
A complex grid of drainage canals and ditches cut the plain into a series of compartments, severely restricting cross-country movement of military vehicles. The most formidable of the barriers were the 240-foot-wide Mussolini Canal and the Colletore delle Acqua Medie, or West Branch of the Mussolini Canal; the former flowed generally from north to south along the beachhead's right flank and the latter flowed southeastward from the direction of the Alban Hills to join the Mussolini Canal about seven miles from the coast. The smooth, sloping banks of these canals dropped into water that varied in depth from ten to twenty feet. Most of the smaller canals were from twenty to fifty feet wide.
Approximately triangular in shape, the Anzio beachhead encompassed much of the plain west of the Mussolini Canal, generally better drained than that to the east of the canal. Except for the few roads along the tops of dikes, the region around Littoria, fifteen miles east of Anzio, had reverted to its ancient state, a virtually impassable marsh. From Terracina, at the southeastern edge of the plain, Highway 7 runs northwest for thirty miles to the town of Cisterna, fifteen miles inland and northeast from the port of Anzio. A section of the Naples-Rome railroad parallels the highway for a short distance before crossing the highway at Cisterna. The Allied beachhead lay southwest of both the highway and the railroad.
The apex of the triangle, whose base rested upon a 20-mile stretch of coastline, pointed like an arrowhead toward Cisterna. Around a large administrative building in the center of Cisterna, mostly in ruins as a result of months of artillery fire, the Germans had built a ring of mutually supporting strongpoints, which had become the hinge of their forward defensive lines.
Inland from Cisterna the coastal plain narrows, rising to a gently rolling corridor about three miles wide and extending from Cisterna in a north-northeasterly direction fourteen miles to Valmontone on Highway 6, at the upper end of the Sacco River, a tributary of the Liri. Dotted with vineyards and orchards and cut by occasional wide, southward-running ravines, the corridor offers terrain generally favorable for military operations. Flanking to the southeast are the steep-sided Lepini Mountains, rising to heights of over 3,000 feet. In the vicinity of the ancient fortress town of Cori, six miles northwest of Cisterna, the slopes of the mountains are covered by olive groves which give way on the higher elevations to bare rock and scrub oak. Footpaths and cart trails similar to those encountered by the II Corps in the Petrella massif offer the only access to that inhospitable region.
Northwest of the corridor are the Alban Hills, whose highest summits are somewhat lower than those of the Lepini Mountains. Thousands of years ago this circular hill mass had been formed by a volcano. Two of the highest hills are the Rocca di Papa and
Monte Cavo, both rising hundreds of feet above the crater floor. Over the years the southeastern rim of the crater eroded to form an elongated ridge about four miles in length, averaging 2,000 feet in height. Rising like a wall behind the town of Velletri, located at a point halfway up the ridge where Highway 7 leaves the coastal plain and enters the hills, the ridge bears the lyrical name of Monte Artemisio. From both Velletri and the ridge behind it the Germans had excellent observation over both the beachhead and the corridor leading from Cisterna to Valmontone.
Extending like fingers from the southern slopes of the Alban Hills and onto the coastal plain, steep-sided ridges formed by ancient lava flows ran past the towns of Velletri and Lanuvio, the latter located five miles to the west of the former. The sides of the ridges were covered with modest vineyards and groves of chestnut trees, but the crests were open and usually cultivated in a patchwork of grain fields.
The Opposing Forces
Reflecting the fluctuations imposed by attack and counterattack in the weeks since the landing at Anzio, the Allies' forward positions by mid-May traced a meandering line across the landscape. From the sea on the southwest they led to a ridge south of the Moletta River, thence to the Anzio-Aprilia-Albano road. From the road the front curved northeastward about five miles to the hamlet of Casale Carano, thence followed the Carano Canal for a short distance before turning southeast to parallel the Cisterna-Campoleone-Rome railroad for some seven miles as far as the west bank of the Mussolini Canal. At the canal the front turned south and followed its west bank for nine miles to the sea. Blocking the most likely avenues of enemy attack across the front were numerous mine fields emplaced by the Allied troops during the winter battles.
Of the U.S. units on the beachhead in February--the 3d and 45th Divisions, the 1st Armored Division's Combat Command A, the 1st Special Service Force (an American-Canadian regimental-sized force), the reinforced 509th Parachute Regimental Combat Team, and the 6615th Ranger Force (three battalions)--only the paratroopers had left the beachhead by mid-May. The survivors of the ranger force had been integrated into the 1st Special Service Force. Those losses had been more than made up in late March by the arrival of the 34th Infantry Division, a veteran of the winter fighting at Cassino. On 28 March that division began relieving the 3d Division, which had been on the front for sixty-seven consecutive days. The 1st Armored Division was also brought up to full strength with the arrival in April of CCB, its second combat command, and other elements of the division.
The British too had shifted some of their units. In early March the 5th Division had replaced the 56th, and the latter, together with some British commandos, left the beachhead. The 1st Division remained, but its 24th Guards Brigade was relieved by the 18th Guards Brigade, the former moving to Naples for rest and reorganization.
By the beginning of April all Allied units had been brought to full strength. The VI Corps, including the two British
divisions, mustered a combat strength of approximately 90,000 men. As planning for the beachhead offensive got under way, Allied units were holding the front from left to right in the following order: the British 5th and 1st Divisions, the U.S. 45th and 34th Divisions, and the 36th Engineer Regiment. In corps reserve were the 3d and 36th Divisions (the latter having arrived on the beachhead by sea on 22 May), the 1st Armored Division, and the 1st Special Service Force.14
The Germans too, after the repulse of their winter attack, had begun to regroup their forces. In mid-March a Jaeger division15 was moved to the Adriatic coast to strengthen the front there, and the Hermann Goering Division was withdrawn to Tuscan bases near Leghorn for rest and reorganization. About the same time, the 26th Panzer and 29th Panzer Grenadier Divisions had also been withdrawn from the Fourteenth Army into army group reserve in the Rome area.16
Facing the Allied beachhead were five divisions divided into two corps. From right to left there were in line the following units: the I Parachute Corps, commanding the 4th Parachute, 65th Infantry, and 3d Panzer Grenadier Divisions, and the LXXVI Panzer Corps with the 362d and 715th Infantry Divisions.
The heavy winter fighting had left most of the divisions somewhat understrength. Although General von Mackensen's army would never regain its February strength, replacements had continued to trickle in. By mid-April the Fourteenth Army had grown to 70,400 men, still considerably less than the approximately 90,000 Allied soldiers assembled on the beachhead.
The Fourteenth Army's artillery units, long-time targets of Allied air attacks, had also incurred heavy losses. Mackensen's artillery had been further plagued by chronic delays in the arrival of ammunition, delays occasioned more by shortages of transport than by lack of supply in dumps. Furthermore, most Allied guns lay beyond range of the self-propelled howitzers and dual-purpose antiaircraft guns which made up the bulk of the Fourteenth Army's artillery. Mackensen's artillery could fire effective counterbattery only with a few 100-mm. guns, although Kesselring had promised that additional heavy pieces were on the way: twelve 210-mm. howitzers and seven batteries of 122-mm. guns from the OKW artillery reserve in France and a railway artillery battery of 320-mm. guns from northern Italy. He also promised to increase ammunition allocations, although in view of German transportation problems that was hardly likely to come about.
Allied Preparations
As the Germans awaited the Allied blow, the leader of the force that was to make the main effort, General Truscott, commander of the U.S. VI Corps, still awaited a decision as to the direction his force was to take once breakout from the beachhead had been achieved. Yet despite General Clark's determination to keep the matter open, Truscott
focused his attention on the plan he deemed most likely to be adopted, the one General Alexander had favored--Operation BUFFALO.
Vital to BUFFALO's success Truscott reasoned, were rapid capture of the enemy's main stronghold at Cisterna and swift occupation of the town of Cori, halfway up the western slopes of the Lepini Mountains. Until those two objectives were in hand, the enemy would control the road network leading to BUFFALO's objective, Valmontone on Highway 6.
On 6 May, the day following General Alexander's visit to VI Corps headquarters, General Truscott outlined for his division commanders a two-phase attack designed to gain those objectives. In the first phase the corps was to drive northeastward to build up along the X-Y Line, a line forming a large arc two miles north and east of Cisterna and extending from Highway 7 as far as the main road from Cisterna to Cori.17 In the second phase the corps was to capture Cori, then to advance northward via Guilianello toward Artena, a road junction about three miles south of Valmontone. From Artena the drive was to continue with a thrust to cut Highway 6, capture Valmontone, and cut the Tenth Army's line of communications.
The armored strength of the VI Corps' offensive was to be provided by the 1st Armored Division, commanded by Maj. Gen. Ernest N. Harmon, a vigorous and able leader given to blunt speaking. The 1st Armored Division had fought in North Africa but, after
GENERAL HARMONthe division landed on the Italian mainland in September 1943, mountainous terrain had denied it more than a minor role in the advance from Salerno to Cassino. During the winter, division headquarters and CCA had joined the VI Corps in the Anzio beachhead, while CCB remained behind with the II Corps on the southern front in order to exploit a projected Fifth Army breakthrough into the Liri valley. In the end, CCB also had to come to Anzio by sea.
A so-called "heavy" armored division, one of three formed in the U.S. Army before a decision to scale down the tank strength of armored divisions, the 1st Armored Division had a TO&E strength of 232 medium tanks and 14,620 officers and men, making it a formidable force with a tank strength a third again greater than a German
panzer division. In addition, the division had an attached tank destroyer battalion, an antiaircraft battalion, and, to supplement its three organic 105-mm. (howitzer) self-propelled artillery battalions, the attached 69th Field Artillery Battalion of 105-mm. self-propelled howitzers. To supplement the division's armored infantry regiment for the offensive, General Truscott attached the 135th Infantry from the 34th Division. There were also two companies from the 83d Chemical Battalion, equipped with 4.2-inch mortars capable of firing smoke and high-explosive shells,18 one company each from the 109th Combat Engineer and self-propelled 636th Tank Destroyer Battalions, and a detachment of the 6617th Mine Clearing Company.
General Harmon's division and the 3d Infantry Division, formerly Truscott's own division, were to lead the breakout offensive. One of the U.S. Army's oldest and most distinguished divisions, the 3d had taken part in the North African and Sicilian campaigns. After Truscott had moved up to corps command, the division came under the command of Maj. Gen. John W. O'Daniel, whose rough features and barracks-yard voice had prompted the nickname "Iron Mike."
For his part, General Harmon objected strongly to pairing an armored
GENERAL O'DANIELand an infantry division for the breakout attempt. Better to follow the conventional pattern, he argued, of holding the armor in reserve as a tool for exploiting an infantry breakthrough. He confided that view to two staff officers of the Fifth Army's G-3 plans section who visited his headquarters on the eve of the offensive. Harmon told his visitors that he expected to lose 100 tanks in the first thirty minutes of the offensive. It was, he declared, "a crazy idea."19 Actually, General Truscott recognized that his decision to use the armored division in the first stage of
the offensive ran counter to current armored doctrine, but he saw the weight of the armor as affording the best possibility of breaking the long-held German positions in the Cisterna sector.20
Under Truscott's plan the 1st Armored Division was, during the offensive's first phase, to advance from positions southwest of Cisterna along a line roughly parallel to Le Mole Canal to cut the railroad northwest of Cisterna, push on to Highway 7, then to the X-Y Line. In the second phase, the division was to move first to a phase line designated the O-B Line, which crossed the corridor between the Alban Hills and the Lepini Mountains three miles south of Velletri. The division's left flank was to keep the Velletri-based enemy north of that line, while the rest of Harmon's troops were, on Truscott's order, to swing northeast and continue the drive on Artena and Valmontone. Maj. Gen. Fred L. Walker's 36th Infantry Division was to move up from corps reserve to take Cori and to reinforce the armored division's attack on Artena.
To the 3d Division, General Truscott gave the crucial task of first isolating, then capturing Cisterna. Unlike Harmon, O'Daniel had complete confidence in the plans for the forthcoming offensive and in the ability of his division to seize Cisterna and continue to the final objective. General O'Daniel's zeal may have been enhanced by an opportunity to even a score with the enemy following a futile attempt by the division to storm Cisterna in January.
While the 3d Division attacked the enemy's center, the division's right flank was to be covered by Brig. Gen. Robert T. Frederick's American-Canadian 1st Special Service Force, advancing from positions just west of the Mussolini Canal to cut Highway 7 southeast of Cisterna and occupy that part of the X-Y Line in that sector. Thereafter, Frederick's men were to be prepared, on corps order, to seize the heights of Monte Arrestino, overlooking Cori from the south, then move northward across the Lepini Mountains to cut Highway 6 east of Valmontone.
On the 1st Armored Division's left, Maj. Gen. William W. Eagles' 45th Division, holding the sector between the Spaccasassi Canal and the Carano Canal, was to cover the left flank of the offensive by an advance as far as the first phase line, which in Eagles' sector ran generally in a northerly direction just west of the village of Carano, some five miles southwest of Cisterna and on the bank of the Carano Canal. As the main attack moved on beyond Cisterna, the division was to keep the enemy in its zone occupied by vigorous patrolling.
Meanwhile, Maj. Gen. Charles W. Ryder's 34th Division, holding the front across the corps center from Le Mole Canal to the Nettuno-Cisterna road, was to screen the final preparations for the offensive and to assist in gapping American mine fields and barbed wire barriers for the attacking units. When relieved from that assignment, the division, less the regiment attached to the armor, was to regroup and prepare to relieve elements of either the 1st Armored Division or the 1st Special Service Force if either should be unable to continue the offensive after reaching the first phase line.
General Truscott had also prepared a
deception plan, Operation HIPPO, designed to deceive the enemy as long as possible as to the offensive's true direction by a strong demonstration on the beachhead's far left flank a few hours before the breakout offensive began. The job of executing HIPPO fell to the British 1st and 5th Divisions, holding that sector of the beachhead perimeter from the Tyrrhenian coast northeastward to the left flank of the 45th Division. Since they were to be withdrawn after the capture of Rome, the two British divisions were to operate under direct control of the Fifth Army without an intervening corps command.21
To support the offensive, the VI Corps assembled an impressive groupment of corps artillery: three battalions of 155-mm. howitzers, a battalion of 8-inch howitzers, and a battery of 240-mm. howitzers. Two British artillery regiments were also attached to corps. Except for a battalion of 105-mm. howitzers that Truscott had attached to the 1st Armored Division, corps artillery was to fire in general support of the offensive. Three battalions of 90-mm. antiaircraft artillery from the 35th Antiaircraft Artillery Brigade were to be prepared to fire on ground targets. With a high muzzle velocity and flat trajectory, antiaircraft guns would be particularly useful against enemy armor and pillboxes. Finally, on D-day, as had been the case when the offense began along the Garigliano, the guns of two cruisers lying offshore were to engage prearranged targets opposite the British sector.22
Several weeks before the anticipated date of the offensive, Truscott directed his corps artillery to begin a daily firing schedule designed to uncover the enemy's defensive fires and further mislead the Germans as to the actual start of the offensive. In view of the defensive strategy that Hitler had urged upon his commanders in Italy such deception was of paramount importance. But this, of course, was unknown to General Truscott. Each morning from different parts of the beachhead guns of various batteries opened a series of barrages, with their time, length, and method of firing frequently changed. At first the Germans replied with large-scale defensive fires, but after a time apparently concluded that the barrages were only another spendthrift American harassment and made little response. This assumption was destined to pay off with a delayed reaction when the Allied artillery preparation for the offensive actually began.23
Truscott's breakout was also to be supported by aircraft from the XII TAC, flying from bases in the vicinity of Naples. Before the offensive, fighter-bombers were to step up their operations against the enemy's line of communications, especially southeast of Rome. Long-range artillery positions and supply installations in the Alban Hills near Frascati and Albano as well as at Velletri and Valmontone were to be bombed and strafed almost daily.24
Beginning at 0625 on D-day and continuing until 1930, fighter-bombers of the XII TAC were to fly twenty-eight
preplanned missions, mostly against artillery positions and troop bivouacs. The airmen were also to provide fighter cover to protect ground forces from hostile air attack, even though for some time the Luftwaffe had been virtually driven from Italian skies. Once the ground forces began their offensive, seventy-two fighter-bombers were to attack enemy positions along the rail line extending northwest from Cisterna, then bomb and strafe enemy artillery in an effort to limit defensive fires in the offensive's early phases. Four fighter-bombers were to attack the town of Cori, and a group of heavies was to hit Velletri and Sezze with demolition and fragmentation bombs.25
Fighter-bombers were to provide close support as the offensive continued, with a forward controller located at the VI Corps command post directing the aircraft to targets of opportunity. Aircraft flying prebriefed missions to specific targets were, upon entering the corps zone, to check in immediately with the forward air controller. If there were no emergency targets, the controller was to release the aircraft to go about assigned missions. Fighter-bombers were also to fly armed reconnaissance along Highways 6 and 7 south of Rome and over the road network between the two highways.26
The freedom of movement long enjoyed by the Allies behind their shield of air supremacy was again demonstrated by the ease with which the Fifth Army, despite numerous small-scale enemy air attacks and harassing artillery fire, assembled over a period of several weeks sufficient supplies at Anzio to sustain the forthcoming offensive. Improvement of the VI Corps' counterbattery fires and antiaircraft defenses and the cumulative effect of the XII TAC's attacks against German artillery positions eventually reduced the effectiveness of enemy action against VI Corps' supply dumps to a negligible factor.27
During the winter most of the VI Corps' supply problems had been caused by a chronic shortage of shipping. As the weather gradually improved and more craft became available, particularly small craft suitable for offshore unloading of Liberty ships, the problems eased. Transportation battalions were soon discharging five or six Liberty ships at a time. During March a peak volume of 157,274 tons was unloaded at the beachhead.28
By mid-May enough stocks to support the VI Corps and its attached units for forty days of offensive operations had been cached in dumps dispersed over the beachhead. The supplies were in addition to those usually maintained to support ten days of normal operations. To save time and personnel after the offensive got under way, several quartermaster truck companies were brought ashore, their vehicles fully loaded with ammunition. Once ashore,
the trucks moved quickly into concealed positions to await D-day.29
Final Moves
Before Truscott could determine the exact H-hour for the offensive, he first had to resolve the conflicting operational requirements of armored and infantry divisions. The infantry, being particularly vulnerable to small arms and mortar fire, quite naturally preferred to begin the attack before daylight. On the other hand, the armored division's tank gunners had to have enough daylight to see the cross-hairs in their gunsights. Since Truscott's staff believed that the infantry could substitute smoke for darkness and that the armored division could find no substitute for its requirements, H-hour was set for one hour after dawn.30
Getting the assault units undetected into positions close to their line of departure, about two or three miles south of the Cisterna-Rome railroad and between the Spaccasassi Creek and the Mussolini Creek, posed a special problem, for the Germans enjoyed superb observation of the entire beachhead area from their vantage points in the flanking hills and mountains. To solve the problem Allied staffs worked out detailed movement schedules for the infantry and artillery to be accomplished during the last two nights before the offensive began.31 Movement of the armor into forward assembly areas was accompanied by tying the movement to the artillery deception plan. For several weeks preceding the offensive, as the artillery fired a daily barrage, the tanks, with no attempt at concealment, rumbled noisily toward the German lines, firing point-blank, then turning and scurrying to the rear. Noting that the tanks always stopped short of their own infantry's forward positions, the Germans soon ceased to react to the maneuver. Each day, once the ground had begun to dry out in mid-May, a few of the tanks slipped off the roads into previously prepared positions. The tactic was repeated until a substantial armored assault force had been assembled close behind the front.32
While the VI Corps made final preparations for the offensive, General Clark in his headquarters at Caserta remained concerned over the direction the offensive should take once the corps had broken out of the beachhead. On the morning of 19 May, Truscott and members of his staff went at Clark's request to the army headquarters. There Clark raised the suggestion that BUFFALO's initial objectives, Cisterna and Cori, be taken as planned, but then, instead of moving to Highway 6, the VI Corps might regroup and turn northwestward into the Alban Hills. Frederick's 1st Special Service Force, in the meantime, could continue toward Artena and Valmontone, the original objectives of Operation BUFFALO. Only after Truscott pointed out that Frederick's force alone was not strong enough for this task did Clark drop the suggestion.33
Yet the suggestion reflected Clark's concern about what effect the enemy's presence on the Alban Hills might have on the VI Corps' advance toward Valmontone and Highway 6. During the conference Clark also informed Truscott that Alexander might order the breakout offensive to begin two days later--on the 21st. Returning to the beachhead on the 19th, Truscott directed part of his corps and divisional artillery to begin displacing forward that night into their previously prepared positions. Until he received more definite word on the jump-off date, that was the only move he sanctioned.34
Alexander himself visited Clark's headquarters the next day. Poor weather predicted for the 21st, Clark told him, might delay the VI Corps its needed tactical air support; he recommended postponing the offensive at least twenty-four, perhaps even forty-eight, hours. Anxious to have the breakout offensive coincide as closely as possible with the Eighth Army's assault against the Hitler Line, Alexander readily agreed. When he radioed the news to Truscott, Clark indicated the possibility of a postponement to the 23d but promised final word by late afternoon of the 21st.35
Postponing the offensive for even twenty-four hours created an awkward and a potentially dangerous situation for the VI Corps. The postponement meant that some units would have to remain in forward assembly areas longer than the forty-eight hours that Truscott intended, increasing the possibility that the Germans might detect their presence and conclude that an offensive was about to begin.
The Germans, meanwhile, were apparently nervous. Throughout the nights of the 20th and 21st the enemy increased his patrolling and artillery fire across the front. One patrol penetrated the 179th Infantry's outpost line in the 45th Division sector on the corps' left flank but withdrew in the face of heavy mortar fire without taking a prisoner.36
At 1715 on the 21st final word on the date of the offensive arrived at Truscott's headquarters. "Operation BUFFALO will be launched at 0630 hours on 23 May," Clark radioed. "I will arrive at Advanced Command Post about noon on Monday [22 May]."37
That night the VI Corps' combat units moved into their assigned assembly areas, while the 109th Engineer Battalion and the 34th Division's engineers began the tedious and hazardous work of clearing gaps through Allied mine fields. The front remained relatively quiet, disturbed only by occasional German shelling that killed three men at a road junction near the 3d Division headquarters and caused minor casualties in the 45th Division's area.
By daylight on 22 May, all units had reached their jump-off positions. Throughout a lovely spring day that invited lounging in the sunshine, the troops instead crouched in dark dugouts, the ruins of farmhouses, and scattered groves of trees along the
drainage canals to avoid being seen by enemy observers. In the meantime, Clark, leaving his chief of staff in charge of the Fifth Army main headquarters at Caserta, moved to the beachhead with his staff, where the army commander established a command post in a tunnel beneath the Villa Borghese, located on a small hill overlooking Anzio harbor.
General Clark confidently awaited the start of the offensive, yet as he did so he was troubled with misgivings over what he termed his "political problems." Three considerations were uppermost in his mind: he wanted above all to be first in Rome and to be there before the imminent invasion of northwestern Europe crowded the Italian campaign off the front pages of the world's newspapers; he was also understandably anxious to avoid destructive fighting within the hallowed city; and, finally, he was persuaded that to follow the strategy Alexander preferred would deny the Fifth Army the first goal and quite possibly the second.38
General Clark had by that time convinced himself that to follow Alexander's strategic concept was pointless. To do so, Clark believed, would shift the burden from the Eighth to the Fifth Army which had already incurred heavy casualties since the spring offensive had begun. "I was determined that the Fifth Army was going to capture Rome," he later recalled, "and I was probably overly sensitive to indications that practically everybody else was trying to get into the act. These indications mounted rapidly in the next few days, and I had my hands full."39 Thus it was that General Clark's rejection of Alexander's strategic concepts for the beachhead offensive cast a threatening shadow over Operation BUFFALO and, with it, Alexander's (and Churchill's) expectations of trapping a major part of the German Tenth Army between the British Eighth and the U.S. Fifth Armies south of Rome.
Footnotes
1. Hq AAI, Opns 0 1, 5 May 44.
2. Brigadier C. J. C. Molony, "History of the Second World War," The Mediterranean and Middle East, Volume V, The Campaign in Sicily and the Campaign in Italy, 3rd September 1943 to 31st March 1944 (London: Her Majesty's Stationery Office, 1973), p. 833.
3. Martin Blumenson, "General Lucas at Anzio," in Command Decisions (Washington, 1960), p. 301; Clark's comments on MS, in CMH files.
4. See Forrest C. Pogue, George C. Marshall, Organizer of Victory (New York: Viking Press, 1973), p. 331.
5. Ibid., pp. 326-27; Mark W. Clark, Calculated Risk (New York: Harper & Brothers, 1950), pp. 283-86.
6. Clark's comments on MS, in CMH files.
7. Ibid.
8. Truscott Personal Radios Sent files, Feb-Jun 1944.
9. Clark Diary, 8 May 44; Clark's comments on MS, in CMH files.
10. Clark Diary, 8 May 44; Sidney T. Mathews, "Clark's Decision to Drive on Rome," in Command Decisions (Washington, 1960), pp. 353-54.
11. Clark, Calculated Risk, p. 352; Clark Diary, 5 May 44.
12. Nicolson, Alex, pp. 252-53.
13. CMDS (Br), The German Operations at Anzio, 22 January to 31 May 1944.
14. DA Hist Div, "American Forces in Action," Anzio Beachhead (22 January-25 May 1944) (Washington, 1947), p. 106.
15. "Jaeger" denotes a light infantry division as contrasted with a standard infantry division.
16. GMDS (Br), The German Operations at Anzio, 22 January to 31 May 1944, pp. 94-95. Unless otherwise cited the following is based upon this source.
17. VI Corps FO 25, 6 May 44. Unless otherwise cited this section is based upon this source.
18. This mortar had been developed from the Stokes Mortar of World War I and had first seen action during the Sicilian campaign in the summer of 1943. After the Chemical Corps adapted the mortar to fire HE, it became an important and useful infantry support weapon with a maximum range of 4,397 yards. See Leo P. Brophy, Wyndham D. Miles, and Rexmond C. Cochrane, The Chemical Warfare Service: From Laboratory to Field, U.S. ARMY IN WORLD WAR II (Washington, 1959).
19. Interv, Sidney T. Mathews with Lt Col T. J. Conway (Chief, Plans Subsection, G-3, Hq Fifth Army, 16 Dec 44-May 45), 27 Jun 50, CMH.
20. Interv, author with Truscott, Mar 62, CMH.
21. Hq VI Corps AAR, 1-31 May 44.
22. VI Corps FO 26, 6 May 44.
23. Lucian K. Truscott, Command Missions (New York: E. P. Dutton and Co., 1954), pp. 368-70.
24. Hq, VI Corps FO 26, 6 May 44, Air annex.
25. Ibid.
26. Ibid.
27. Wide dispersion of supply dumps helped account for the low loss rate. Of the nine million gallons of POL shipped to the beachhead, for example, less than 1 percent was lost to enemy action. See William M. Ross and Charles F. Romanus, The Quartermaster Corps: Operations in the War Against Germany, U.S. ARMY IN WORLD WAR II (Washington, 1965), pp. 96-114. See also Fifth Army G-4 Jnl, May 44, and DA Hist Div, Anzio Beachhead, pp. 107-11.
28. Fifth Army G-4 Jnl, May 44.
29. Ibid.
30. VI Corps G-3 Jnl, May 44; Truscott Personal File; Interv, Mathews with Gen Harmon, 14 Dec 48, CMH.
31. Truscott, Command Missions, pp. 367-68.
32. Monograph, "American Armor at Anzio," The Armored School, Ft. Knox, May 49, pp. 87-88.
33. Truscott, Command Missions, pp. 370-71; Clark's comments on MS, in CMH files.
34. Truscott, Command Missions, pp. 376-71; Fifth Army History, Part V, p. 108.
35. Clark, Calculated Risk, pp. 352-53; Clark Diary, 20 May 44.
36. VI Corps G-3 Jnl, May 44.
37. Msg, Clark to Truscott, 211705B May 44, Truscott Personal Radios Received files, Feb-Jun 44.
38. Clark, Calculated Risk, pp. 351-52.
39. Ibid., p. 357; Clark's comments on MS, in CMH files.
