World War II: Battle of Monte Cassino

Monte Cassino Abbey after the bombing
Deutsches Bundesarchiv (German Federal Archive), Bild 146-2005-0004

The Battle of Monte Cassino was fought January 17 to May 18, 1944, during World War II (1939 to 1945).

Fast Facts: Battle of Monte Cassino

Dates: January 17 to May 18, 1944, during World War II (1939-1945).

Allies Armies and Commanders

German Armies and Commanders

  • Field Marshal Albert Kesselring
  • Colonel-General Heinrich von Vietinghoff
  • German 10th Army


Landing in Italy in September 1943, Allied forces under General Sir Harold Alexander began pushing up the peninsula. Due to the Apennine Mountains, which run the length of Italy, Alexander's forces advanced on two fronts with the Lieutenant General Mark Clark's US Fifth Army on the east and Lieutenant-General Sir Bernard Montgomery's British Eighth Army on the west. Allied efforts were slowed by poor weather, rough terrain, and a tenacious German defense. Slowly falling back through the fall, the Germans sought to buy time to complete the Winter Line south of Rome. Though the British succeeded in penetrating the line and capturing Ortona in late December, heavy snows prevented them from pushing west along Route 5 to reach Rome. Around this time, Montgomery departed for Britain to aid in planning the invasion of Normandy and was replaced by Lieutenant General Oliver Leese.

To the west of the mountains, Clark's forces moved up Routes 6 and 7. The latter of these ceased to be usable as it ran along the coast and had been flooded at the Pontine Marshes. As a result, Clark was forced to use Route 6 which passed through the Liri Valley. The southern end of the valley was protected by large hills overlooking the town of Cassino and atop which sat the abbey of Monte Cassino. The area was further protected by the fast-flowing Rapido and Garigliano Rivers which ran west to east. Recognizing the defensive value of the terrain, the Germans built the Gustav Line section of the Winter Line through the area. Despite its military value, Field Marshal Albert Kesselring elected not to occupy the ancient abbey and informed the Allies and Vatican of this fact.

First Battle

Reaching the Gustav Line near Cassino on January 15, 1944, the US Fifth Army immediately began preparations to assault the German positions. Though Clark felt the odds of success were low, an effort needed to be made to support the Anzio landings which would occur further north on January 22. By attacking, it was hoped that German forces could be drawn south to allow Major General John Lucas' US VI Corps to land and quickly occupy the Alban Hills in the enemy rear. It was thought that such a maneuver would compel the Germans to abandon the Gustav Line. Hampering Allied efforts was the fact Clark's forces were tired and battered after fighting their way north from Naples.

Moving forward on January 17, the British X Corps crossed the Garigliano River and attacked along the coast putting heavy pressure on the German 94th Infantry Division. Having some success, X Corps' efforts forced Kesselring to send the 29th and 90th Panzer Grenadier Divisions south from Rome to stabilize the front. Lacking sufficient reserves, X Corps was unable to exploit their success. On January 20, Clark launched his main assault with the US II Corps south of Cassino and near San Angelo. Though elements of the 36th Infantry Division were able to cross the Rapido near San Angelo, they lacked armored support and remained isolated. Savagely counterattacked by German tanks and self-propelled guns, the men from the 36th Division were ultimately forced back.

Four days later, an attempt was made north of Cassino by Major General Charles W. Ryder's 34th Infantry Division with the goal of crossing the river and wheeling left to strike Monte Cassino. Crossing the flooded Rapido, the division moved into the hills behind the town and gained a foothold after eight days of heavy fighting. These efforts were supported by the French Expeditionary Corps to the north which captured Monte Belvedere and assaulted Monte Cifalco. Though the French were unable to take Monte Cifalco, the 34th Division, enduring incredibly harsh conditions, battled their way through the mountains towards the abbey. Among the issues faced by Allied forces were large areas of exposed ground and rocky terrain that precluded digging foxholes. Attacking for three days in early February, they were unable to secure the abbey or the neighboring high ground. Spent, II Corps was withdrawn on February 11.

Second Battle

With the removal of II Corps, Lieutenant General Bernard Freyberg's New Zealand Corps moved forward. Pushed into planning a new assault to relieve pressure on the Anzio beachhead, Freyberg intended to continue the attack through mountains north of Cassino as well as advance up the railroad from the southeast. As planning moved forward, a debate began among the Allied high command regarding the abbey of Monte Cassino. It was believed that German observers and artillery spotters were using the abbey for protection. Though many, including Clark, believed the abbey to be vacant, increasing pressure ultimately led Alexander to controversially order the building to be bombed. Moving forward on February 15, a large force of B-17 Flying Fortresses, B-25 Mitchells, and B-26 Marauders struck the historic abbey. German records later showed that their forces were not present, through the 1st Parachute Division moved into the rubble after the bombing.

On the nights of February 15 and 16, troops from the Royal Sussex Regiment attacked positions in the hills behind Cassino with little success. These efforts were hampered by friendly fire incidents involving Allied artillery due to the challenges of aiming accurately in the hills. Mounting his main effort on February 17, Freyberg sent forward the 4th Indian Division against German positions in the hills. In brutal, close-in fighting, his men were turned back by the enemy. To the southeast, 28th (Māori) Battalion succeeded in crossing the Rapido and captured the Cassino railroad station. Lacking armor support as the river could not be spanned, they were forced back by German tanks and infantry on February 18. Though the German line had held, the Allies had come close to a breakthrough which concerned the commander of the German Tenth Army, Colonel General Heinrich von Vietinghoff, who oversaw the Gustav Line.

Third Battle

Reorganizing, Allied leaders began planning a third attempt to penetrate the Gustav Line at Cassino. Rather than continue along previous avenues of advance, they devised a new plan which called for an assault on Cassino from the north as well as an attack south into the hill complex which would then turn east to assault the abbey. These efforts were to be preceded by intense, heavy bombing which would require three days of clear weather to execute. As a result, the operation was postponed three weeks until the airstrikes could be executed. Moving forward on March 15, Freyberg's men advanced behind a creeping bombardment. Though some gains were made, the Germans rallied quickly and dug in. In the mountains, Allied forces secured key points known Castle Hill and Hangman's Hill. Below, the New Zealanders had succeeded in taking the railroad station, though fighting in the town remained fierce and house-to-house.

On March 19, Freyberg hoped to turn the tide with the introduction of the 20th Armoured Brigade. His assault plans were quickly spoiled when the Germans mounted heavy counterattacks on Castle Hill drawing in the Allied infantry. Lacking infantry support, the tanks were soon picked off one by one. The next day, Freyberg added the British 78th Infantry Division to the fray. Reduced to house to house fighting, despite the addition of more troops, Allied forces were unable to overcome the resolute German defense. On March 23, with his men exhausted, Freyberg halted the offensive. With this failure, Allied forces consolidated their lines and Alexander began devising a new plan for breaking the Gustav Line. Seeking to bring more men to bear, Alexander created Operation Diadem. This saw the transfer of the British Eighth Army across the mountains.

Victory at Last

Redeploying his forces, Alexander placed Clark's Fifth Army along the coast with II Corps and the French facing the Garigliano. Inland, Leese's XIII Corps and Lieutenant General Wladyslaw Anders' 2nd Polish Corps opposed Cassino. For the fourth battle, Alexander desired II Corps to push up Route 7 towards Rome while the French attacked across the Garigliano and into the Aurunci Mountains on the west side of the Liri Valley. To the north, XIII Corps would attempt to force the Liri Valley, while the Poles circled behind Cassino and with orders to isolate the abbey ruins. Utilizing a variety of deceptions, the Allies were able to ensure that Kesselring was unaware of these troop movements.

Commencing at 11:00 PM on May 11 with a bombardment using over 1,660 guns, Operation Diadem saw Alexander attack on all four fronts. While II Corps met heavy resistance and made little headway, the French advanced quickly and soon penetrated the Aurunci Mountains before daylight. To the north, XIII Corps made two crossings of the Rapido. Encountering a stiff German defense, they slowly pushed forward while erecting bridges in their rear. This allowed supporting armor to cross which played a key role in the fighting. In the mountains, Polish attacks were met with German counterattacks. By late on May 12, XIII Corps' bridgeheads continued to grow despite determined counterattacks by Kesselring. The next day, II Corps began to gain some ground while the French turned to strike the German flank in the Liri Valley.

With his right-wing wavering, Kesselring began pulling back to the Hitler Line, approximately eight miles to the rear. On May 15, the British 78th Division passed through the bridgehead and began a turning movement to cut off the town from the Liri Valley. Two days later, the Poles renewed their efforts in the mountains. More successful, they linked up with the 78th Division early on May 18. Later that morning, Polish forces cleared the abbey ruins and hoisted Polish flag over the site.


Pressing up the Liri Valley, the British Eighth Army immediately attempted to break through the Hitler Line but was turned back. Pausing to reorganize, a major effort was made against the Hitler Line on May 23 in conjunction with a breakout from the Anzio beachhead. Both efforts were successful and soon the German Tenth Army was reeling and facing being surrounded. With VI Corps surging inland from Anzio, Clark shockingly ordered them to turn northwest for Rome rather than cut off and aid in the destruction of von Vietinghoff. This action may have been the result of Clark's concern that the British would enter the city first despite it being assigned to Fifth Army. Driving north, his troops occupied the city on June 4. Despite the success in Italy, the Normandy landings two days later transformed it into a secondary theater of the war.

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Hickman, Kennedy. "World War II: Battle of Monte Cassino." ThoughtCo, Apr. 5, 2023, Hickman, Kennedy. (2023, April 5). World War II: Battle of Monte Cassino. Retrieved from Hickman, Kennedy. "World War II: Battle of Monte Cassino." ThoughtCo. (accessed June 4, 2023).