The Battle of Monte Cassino: Italy’s Monastery Fortress

The Battle of Monte Cassino was one of the Italian Campaign's most brutal fights, lasting four months and leading to catastrophic destruction.

Jun 18, 2022By Turner Collins, BA History
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In July of 1943, the Western Allied forces landed in Italy, intent on knocking out one of the three Axis powers and bringing the war to Germany’s southern borders. The road to Rome and the industrial heartland of northern Italy would be a difficult one, with countless mountain valleys and fortified defensive lines that the Germans had constructed in preparation for the Allies’ assault. One of the most formidable was the infamous Gustav Line. Sitting on the southern-most portion of the Gustav Line was the early medieval abbey of Monte Cassino, founded in AD 529. It would be here that one of the most hard-fought and costly battles for the western Allies took place, the Battle of Monte Cassino. This, along with the concurrent Battle of Anzio, would hold the Allies in place for just over four months. The hilltop abbey itself required four separate attempts and the near-total destruction of the historic site itself to finally breach.


The War Leading Up to the Battle 

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Commonwealth forces in North Africa, via National Army Museum, London


For years, Europe had been engulfed in the Second World War, with battles taking place not just across the continent but likewise in Asia and Africa. The Axis power of Italy had begun its war in North Africa, hoping to take control of British territory and shipping lanes through the Mediterranean, creating a Mare Nostrum. It very quickly became clear that Fascist Italy was in no condition to effectively wage war, with its equipment plagued with design flaws, leadership rifled with incompetence, and its industrial base lacking well behind most other participants of the war. As such, it quickly became apparent to the Nazi leadership in Germany that Italy would require almost constant assistance in the form of leadership, equipment, and soldiers.


This would result in the North Africa Campaign, a long series of back and forth battles between the western Allies and the combined Italian-German forces, headed by the renowned German general Erwin Rommel, the Desert Fox. Eventually, Axis forces would be routed from Northern Africa, retreating to Sicily and Italy, only to be followed by the Allies soon after. In the east, Russia was in a constant struggle against the bulk of the German army and constantly requested new fronts to be opened. Landing in mainland Italy in September of 1943 on the farthest southern tip, the Allies’ plan was simple: to advance up the “boot” of Italy, capture Rome, and advance against Germany from the south.


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Allied soldiers marching up the Italian peninsula, via National Army Museum, London


Italy itself would capitulate days after Allied forces landed on the mainland, only for the German troops still occupying most of Italy to turn on their former allies, killing and disarming much of their military and installing Mussolini as the head of a puppet “Italian Social Republic.” Despite this, Italy was largely out of the war by this point. The fighting fell predominantly to the Germans, who constructed a series of defensive lines up along the entire mountainous center of Italy, intent on stopping the Allies’ advance north. One of the most impressive of these, the first major line was known as the Winter Line, all centered around the heavily-fortified Gustav Line, the southernmost point of which was guarded by an impressive number of cliff-top fortifications and the hilltop abbey of Monte Cassino.

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The Advance to Rome

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Monte Cassino restored in the modern-day, via the Website of the Republic of Poland


Landing on Italy’s eastern and western coasts in the late summer and early fall of 1943, the Allies would find themselves met with dug-in defenders, slowing their advances north across nearly every hill and valley. Initially, it was believed that the Allies would hold Rome by October, though this was quickly dismissed as impossible. Even with decent progress, the Allied forces were forced to stop with the arrival of winter, where snow would block any passage through most of the mountains, and poor weather would render aircraft cover limited. Because of the impassable central mountains, it was decided that the coast, which remained relatively warm even during the winter, would be the main avenue of attack on Rome.


Along with the main advance up the western coast, a large-scale landing was prepared to land at Anzio, located roughly one hundred kilometers behind the town of Cassino. It was believed that this landing would threaten the German rear and force them to abandon their positions closer to Rome. However, what Allied command didn’t know, was that the Gustav Line was considered to be the main defensive line of the Germans in Italy at the time, and would not be abandoned without a fierce fight.


The dual assault on Monte Cassino and Anzio would begin in early January, as Allied landing craft in the Mediterranean would soon be recalled to England to prepare for Operation Overlord. Though German troops had not occupied the actual abbey of Monte Cassino and having informed the Allies and the Vatican of such, some Allied observation planes believed that they had spotted Germans in the complex, though none of these claims would ever be confirmed. With this, the Allied assaults would begin.


The First Attempt at Monte Cassino

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Allied artillery striking Monte Cassino, with the town of Cassino visible below, via National Army Museum, London


The first assault on the Gustav Line and Monte Cassino would come on January 17th, soon followed by the American-led landings at Anzio on the 22nd. The amount of time taken to prepare for the assault was lacking at best, as the main Allied forces had only arrived two days prior, on the 15th. To keep the timetable for the landings at Anzio, the attack would be launched well before the Allied forces were able to organize themselves and recover from the fighting in the south of Italy. The British spearheaded the assault, which commenced with the crossing of the Garigliano river, forcing Germany to commit some of its reserves from Rome to the front, which had been part of the desired effect, lessening the German reserves in preparations for their landings on the coast. A few days later, on the 20th, the Americans would like-wise cross, though they would meet heavily entrenched positions and well-coordinated artillery fire, believed to be spotted from the cliffs around Monte Cassino itself. In the span of two days, the majority of the US forces that crossed the river would be wiped out.


While French Colonial forces made some progress in the north, they were not able to break through the German lines. Likewise, at Anzio, the landings, while successful, had become bogged down as German forces rapidly re-deployed to encircle the Allied troops and flooded the area, creating a large man-made marsh in which the Allies now found themselves trapped. Eventually, by the 11th of February, the forces attempting to take Monte Cassino were forced to withdraw, having suffered massive casualties, and were replaced by fresh troops from the New Zealand Corps.


The Second Battle of Monte Cassino & the Destruction of the Abbey

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Allied bombers dropping ordinance on Monte Cassino, via Liberation Route Europe


With the American landing at Anzio having bogged down unexpectedly, the front at Monte Cassino suddenly found itself pressured to advance to relieve the encircled landing forces. As a result, the New Zealand regiments and Indian troops moved up and were barely given enough time to prepare before attacking, much like the first wave of Americans before. Likewise, it was at this point that the abbey of Monte Cassino itself was considered a target. There was a split between Allied command, those who believed that the site harbored German defenders and observers, and those who saw no such thing.


It had been publicly stated to the Vatican by German forces in Italy that they would not use the abbey as a defensive position but instead occupy the areas around the abbey grounds. The Allies, refusing to believe that this was true, ultimately decided to bomb the monastery, intending on flattening it to the ground to deny it to the Germans as a defensive position.


Beginning on the 15th of February, Allied bombers and artillery opened up on Monte Cassino, pouring over eleven hundred tons of high explosive and incendiary bombs onto the historic abbey. In perhaps one of the most embarrassing blunders of the war, the Germans had not been using the abbey at all, having remained true to their word, and all the bombings had served to do was to kill some two hundred and thirty Italian civilians seeking refuge there.


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The abbey of Monte Cassino post-battle, via The National WW2 Museum, New Orleans


With Monte Cassino now in ruins, the Germans felt that there was no longer any point in keeping away from the historic site, and quickly filtered in to occupy the still formidable ruins, turning it into a strong point and fortress for the remaining duration of the battle. After several days of bombardment, the second offensive was launched along similar lines as the first, with Indian and Commonwealth forces pushing into the mountains from the north over the Rapido river while New Zealand forces pressed up to the town of Cassino from the south.


Once again crossing the rivers proved difficult and establishing a beachhead or pushing up the steep mountains leading to the abbey proved all but impossible. Once again, even with the famed Gurkha mountain troops, the Allies could not dislodge the German defenders, finding themselves pushed back with immensely high casualties. If anything, thanks to the unnecessary and destructive bombing of the Monte Cassino monastery, all the second battle had done was give the Germans an even stronger foothold.


The Final Battle: The Spring Offensives

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The town of Cassino and the abbey above, via History of War


As the second assault ended in just as large a failure as the first, it was decided that the American forces at Anzio would simply have to hold on and that favorable conditions and the end of winter would need to come before another assault was made on the German lines. For almost a month, the Allies sat and gathered their strength, waiting for a window of three days of clear weather to coordinate their aircraft, artillery, and ground forces for a third assault.


With an optimistic weather forecast, the third battle would begin on the 15th of March, with New Zealand, Indian, and Commonwealth forces leading the attack again. Despite a massive preliminary bombardment, the Germans were quickly able to reorganize themselves and mount a counter-attack on the advancing Allies. Worse still, the weather forecast turned out to be mistaken, and the troops found themselves in a total downpour, turning the bombed-out landscape into a mud- and crater-filled mess similar to the fields of the First World War.


An attempted surprise attack by Allied tanks found itself ambushed by German forces and, without any infantry support, were completely wiped out, losing all their vehicles. With their armor decimated, and flanks exposed to the cliffs, their advance was completely bogged down by rain and mud. The Allies were forced to admit that after eight days of fighting, their troops were exhausted and depleted and withdrew once again.


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Map of the battle plan for the fourth and final assault on the Gustav line, via Matthew Parker


The final battle of Monte Cassino would be launched months later, known as Operation Diadem. The lessons of rushed attacks and poor weather had finally convinced the Allies that nothing short of a large-scale, coordinated offensive across a wide front would break the Gustav Line. In order to accomplish this, more divisions were moved up, including American, Polish, and Indian forces along with a division of Canadian tanks. The Allies prepared this offensive over the span of two months, with small troop numbers moving and building along the front to avoid arousing German suspicion. This, along with fabricated training and communications, suggested to the Germans that a second naval landing would occur north of Rome, drawing away their reserves.


Finally, after months of failed offensives, the Allies conducted a final, massive push on May 11th, reaching all the way from the mountains of the Rapido River to the coast. A number of factors helped the Allies in this fourth attempt, including far better weather and ground conditions, which allowed their troops to more easily advance. Furthermore, a large detachment of French colonial mountain troops was able to cross a section of the undefended mountain, believed to be impassable by the Germans, allowing them to threaten German supply lines and the flanks.


Finally, by holding a bridgehead at the town of Cassino long enough, Canadian armor was able to push over the Rapido River and exploit the beachhead made by the infantry. Ultimately, it would be the Polish who reached the abbey first through brutal up-hill fighting, to the point where only a few men were left fit enough to climb the last stretch into the abandoned monastery to raise the Polish flag on May 17th.


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German Paratroopers fighting at Monte Cassino, via History of War


While the Gustav Line had been broken, the Germans would start to retreat up the peninsula towards successive defensive lines. A simultaneous breakout at Anzio failed to entrap the retreating German defenders as the American General in charge, Mark Clark, decided instead to rush his men to the lightly-defended Rome in order to secure glory as the first ones into the city, rather than trapping the retreating German 10th army. Ultimately, the Germans would continue their fighting retreat up the peninsula, and Rome would fall on the 4th of June, 1944, thanks entirely to the long and bloody battles on the slopes of Monte Cassino.

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By Turner CollinsBA HistoryTurner has always had a passion for history and a love of sharing this with others. Having worked with a number of museums on his native Vancouver Island he hopes that his interest proves infectious with others. Having completed his BA in History in 2021 he looks forwards to continuing with his academic learning in pursuit of a MA. When possible he loves to travel, seeking to gather as many new experiences as possible wherever he can.