Allied operation to cross the Garigliano river in southern central Italy by Lieutenant General Sir Richard McCreery’s British X Corps of Lieutenant General Mark W. Clark’s US 5^th Army (17 January 1944).

By the start of 1944, the 5^th Army, operating on the left of the Allied advance to the north through Italy, had reached the German ‘Gustav-Linie’ defences along the line of the Garigliano river. In the stalemate which now followed, the Allies felt that they had to wear away the German strength on the northern side of this river barrier, while the Germans considered that here they had been offered an excellent opportunity of inflicting so telling a blow on the Allies, as the latter tried to prise the Germans out of prepared defences in ideal defensive terrain, that the Allies would drop, or at least delay for many months, the whole idea of an invasion of North-West Europe.

General the Hon. Sir Harold Alexander, commanding the Allied Central Mediterranean Force in Italy, ordered a head-on offensive across the Garigliano and Rapido rivers, and thus through the ‘Bernhard-Linie’ and ‘Gustav-Linie’ defences, in the expectation that these operations would combine with the ‘Shingle’ landing of Major General John P. Lucas’s US VI Corps at Anzio to compel the Germans to fall back to the north. In this thinking Alexander and the Allies seriously overestimated the effect of ‘Shingle’ on the German high command, and hoped to frighten the Germans into withdrawing from their ‘Gustav-Linie’ positions, on which they had spent so much effort and which, despite the pressure being exerted by the 5^th Army’s attacks, was not just settling into a good defensive position but also suggesting that it might be an effectively impregnable position.

For their part, the Germans saw in ‘Shingle’ a superb chance to achieve the type of victory which would most seriously damage British and US morale, namely the destruction of a powerful amphibious landing. The Germans felt that they had not destroyed the ‘Husky’ (i) and ‘Avalanche’ landings on Sicily and at Salerno because the Italians had failed them. With Italy now out of the equation as a result of its armistice of 8/9 September with the Allies, the Germans felt that they could handle the Allied landing with the speedy lack of compromise which would effectively demonstrate the danger inherent in any operation across the English Channel. In the event, the roles of Anzio and Cassino were reversed: on the Allied side the fight for Cassino became the rescuer of the lodgement at Anzio instead of Anzio helping to create conditions for a breakthrough at Cassino; and on the German side, defeat instead of a decisive victory at Anzio endangered German morale, and led to the debilitation of German strength and enthusiasm which victory at Cassino could not counteract.

Neither side frightened the other in the way in which it had hoped: the Germans clung to the ‘Gustav-Linie’ defences in spite of the threat to their rear, and the Allies defeated the German attempt to destroy the Anzio beach-head in spite of the crushing concentrations of troops which the Germans brought against it.

Unwittingly, the Germans helped Alexander to achieve his primary aim of drawing troops away from ‘Overlord’, while the Allies destroyed their own chances of mounting their high-priority ‘Anvil’ against southern France concurrently with ‘Overlord’. Thus each side miscalculated the odds and paid a heavy price for its miscalculations.

By 15 January the initial pair of steps in the Allied winter offensive had been successfully completed. Major General Geoffrey T. Keyes’s US II Corps was on the Rapido river to each side of Cassino and preparing to break into the Liri river valley, and Général de Corps d’Armée Alphonse Pierre Juin’s Corps Expéditionnaire Français was causing Generalleutnant Fridolin Ritter und Edler von Senger und Etterlin considerable concern about the northern flank of his XIV Panzerkorps within Generaloberst Heinrich-Gottfried von Vietinghoff-Scheel’s 10^th Army.

Thus was the scene set for the third operation, namely the X Corps’ attack over the Garigliano river, which has its origins in the confluence of the Rapido and Liri rivers and flows to the west into the Tyrrhenian Sea at a point to the south of Minturno.

The German positions on the Garigliano were held by Generalleutnant Bernhard Steinmetz’s untried 94^th Division, which had the difficult tasks of defending the river as well as the coast around the Gulf of Gaeta. Steinmetz made use of the standard German tactic on a major river line, deploying the main strength of his division on the high ground behind the river with a line of strong outposts on the river. One of his regiments held the Minturno ridge from the sea to the valley of the Ausente river, another occupied the Castelforte ridge from the Ausente in the north to the inter-divisional boundary with Generalleutnant Eberhard Rodt’s 15^th Panzergrenadierdivision on the southern edge of the Liri river valley, and the third was disposed in rear of the division’s seaward flank to look after the coastal sector. Having been in position along the lower Garigliano for some weeks, the 94^th Division had been able to prepare its positions with some care. All the obvious crossings over the river had been extensively mined and were held by outposts in fortified strongpoints on both banks, and the coastal beaches were also well mined and wired.

McCreery planned his corps’ attack on the 94^th Division using two divisions, each with two brigades in the assault wave and one in reserve. Major General G. C. Bucknall’s 5^th Division from the 8^th Army was to attack in the coastal sector astride Highway 7 with the Minturno ridge as its objective, while Major General G. W. R. Templer’s 56^th Division was to attack the Castelforte positions to secure the high ground overlooking the road running up the Ausente river valley to Ausonia and the rear of the ‘Gustav-Linie’ positions in the Liri river valley. The latter division was also allocated a fourth brigade with which to exploit to the north up the Ausente river as soon as Minturno and Castelforte had been taken.

The X Corps’ third formation, Major General J. L. I. Hawkesworth’s 46^th Division, was not to take part in this operation as it was to support the flank of the US II Corps when it attacked slightly later across the Rapido river. The 46^th Division’s target was to be the southern edge of the Liri and Rapido river valleys in the Sant’Ambrogio area.

As the appearance of the 8^th Army’s 5^th Division on the Garigliano would alert the Germans to the imminence of a major attack, the 56^th Division was to cover the 5^th Division’s front until the last possible moment.

Unlike the Volturno river crossing, which had been an extemporised affair, the X Corps’ assault on the Garigliano river positions was very considerable better planned and prepared, with much bridging equipment and more engineers to use it. However, all concerned appreciated that it was be a notably difficult and potentially costly undertaking to cross a fast-flowing waterway of the size of the Garigliano river during winter and with all the possible crossing points overlooked by German artillery observation posts. The British engineers also had to use the existing road approaches to the river because of the softness of the going the rain-sodden fields elsewhere, and these roads were sure to be registered by the German artillery. To overcome this difficulty it was decided to use some 14 rafts, including two large and strong enough to support armour, in the early stages of the attack and not to attempt the construction of bridges until the artillery observation posts with a direct line of sight to the river had been removed from the bridge sites. On the seaward flank, landing craft and DUKW amphibious trucks would ferry tanks and artillery round the mouth of the river and along the coast.

The operation was also rendered more complex by the difficulty of bringing up and deploying the army group and corps artillery which would support the undertaking. Highway 7 was the only good road, so it was along this that the artillery and its ammunition had to be moved, and once these guns and their ammunition had reached the forward area they had to be concealed on the forward slopes of the valley’s southern side, potentially in full view of the German artillery observers.

Finally, the German outposts on the southern side of the Garigliano river had to be overcome in a manner which would not arouse German fears that a major river-crossing operation was about to take place. The assembly, deception and preliminary logistic measures all proceeded according to plan, and the outposts were forced to withdraw without raising an undue level of alarm in the Germans.

When the ‘Panther’ (ix) offensive got under way at 21.00 on 17 January, the 94^th Division was therefore taken by complete tactical surprise, and by the break of day on 18 January the X Corps had moved 10 battalions across the river, with rafts working behind them to bring over anti-tank guns and other heavy weapons. During 18 January both British divisions expanded their initial bridgeheads. The 5^th Division on the seaward flank had great difficulty with minefields on each side of Highway 7 and on the beaches, and the situation was not eased by the fact that the poor navigation of the leading wave of landing craft meant that some of the armour arrived on a beach to the south rather than to the north of the river’s mouth. Even so, by the evening of 18 January the 5^th Division was firmly established on the Minturno ridge and the 56^th Division, which had first launched feint attacks in the area just below Sant’Ambrogio, well above its intended crossing side, had then regrouped and hurled itself across the river to reach positions on the high ground to each side of Castelforte, although the town itself remained in German hands.

The British build-up of both bridgeheads was slow because it depended on rafting troops and vehicles over the river. The first 9-ton bridge had been thrown over the river by dawn on 19 January, but was soon destroyed by German artillery fire. The first 30-ton bridge was not opened until the early hours of 20 January. Even then the bridges could only be used by night, because, although the bridges themselves were out of sight below the river’s flood banks, the approach roads were under German artillery observation and were shelled whenever a vehicle tried to reach the river in daylight. This situation remained typical of the next three months as the German artillery observation posts were not cleared away from the river line until the ‘Gustav-Linie’ defences finally collapsed in May.

The X Corps’ build-up was nonetheless fast enough to allow the troops in the bridgeheads to defeat the 94^th Division’s immediate counterattacks and the early counterattacks by German reserve divisions from 30 January. von Senger und Etterlin appreciated that the Allies were trying to turn both flanks of his XIV Panzerkorps, and while he was able to halt the Corps Expéditionnaire Français, at least temporarily, by the use of his own reserves, he nonetheless requested the German commander in the Italian theatre, Generalfeldmarschall Albert Kesselring, to release Generalmajor Walter Fries’s 29^th Panzergrenadierdivision and Generalleutnant Gerhard Graf von Schwerin-Krosigk’s 90^th Panzergrenadierdivision, which were in army group reserve in the area to the south of Rome, with which to counterattack the threat of the X Corps.

Kesselring found himself in a quandary, for these divisions were purposefully being held back behind the XIV Panzerkorps to strike at any Allied landing behind the front, and his instincts told Kesselring that such a landing was inevitable. German intelligence had found no evidence that such a landing was imminent, however, and if Kesselring ignored the X Corps’ advance on Ausonia, the ‘Gustav-Linie’ defences would be rolled up from the south.

At this stage the ‘Hitler-Riegel’ defences, which ran across the Liri river valley some miles behind Cassino blocking the approaches to the Ausente river valley, were not ready for occupation. Against his better judgment, Kesselring ordered General Alfred Schlemm, commander of the I Fallschirmkorps based in the area of Rome, to move to the south with the 29^th Panzergrenadierdivision, the 90^th Panzergrenadierdivision and elements of Generalleutnant Paul Conrath’s Panzerdivision ‘Hermann Göring’ to restore the situation in the 94^th Division’s sector.

Schlemm’s counterattack started on 20 January and led to bitter fighting in which the X Corps just held its ground, inflicting heavy casualties on the three German mobile divisions. Any idea of exploitation up the Ausente river valley faded as identifications of these German reinforcements reached the headquarters of the 5^th Army. At the Allied Central Mediterranean Force level, the appearance of these divisions was welcomed as a sign that Alexander’s strategy was working. If all went well there would be no German reserves left near Rome with which Kesselring could oppose the imminent ‘Shingle’ landing at Anzio.