The Benedictine monastery, stormed by the Lombards in 589, the Saracens in 884, and the Normans in 1030 and temporarily 🧲 deserted, was each time refounded on the original site. The parent house of Western monasticism, it was during the Middle 🧲 Ages an outstanding centre of the arts and of learning. Paul the Deacon (c. 720–799) wrote his history of the 🧲 Lombards there, founding a long tradition of historical scholarship; and the radical reconstruction of the abbey in the 11th century 🧲 by the abbot Desiderius (later Pope Victor III) was a major event in the history of Italian architecture. In 1349 🧲 the buildings suffered from a severe earthquake, and the church and monastery were almost entirely rebuilt in the 16th and 🧲 17th centuries.

During World War II (1944) Cassino was a key point in the German winter defensive line (Garigliano-Sangro) blocking the 🧲 Allied advance to Rome. At the beginning of January 1944 the U.S. 5th Army won a position facing Cassino across 🧲 the Garigliano River. Heroic fighting by Allied troops met heroic German resistance in three savage battles. On February 15 the 🧲 Allies bombed and demolished the Benedictine monastery, erroneously believing that the Germans had occupied and fortified it. Actually, the Germans 🧲 were able to remove both the monks and the treasures of the abbey; and, after the bombardment ceased, they in 🧲 fact occupied and fortified the ruins. A month later Allied aircraft dropped 1,400 tons of bombs on Cassino, leaving the 🧲 town so heaped with rubble that tanks could not operate until bulldozers cleared paths for them. Finally in mid-May the 🧲 Allies did break through German lines and, joined a few days later by forces bursting out of the Anzio beachhead, 🧲 were able to take Rome. German and Allied war cemeteries, still visited by thousands annually, mark the scenes of the 🧲 fighting.

After the war, both the town and the abbey were rebuilt on their previous sites, the town on a completely 🧲 new plan, the abbey following substantially the lines of its predecessor. Little or nothing of the abbey’s decorative detail was 🧲 recoverable, but the famous bronze doors, cast in Constantinople for the abbot Desiderius in 1066, were found and restored. The 🧲 archives, library, and some paintings were saved. Of ancient Casinum the only monuments of note are the amphitheatre, the theatre, 🧲 and the ruins of the Cappella del Crocifisso, a Roman mausoleum converted into a church in the 10th century. Of 🧲 the medieval town little more than the site of the upper town, clustered around the ruins of Rocca Ianula, can 🧲 be discerned.

An agricultural and commercial centre, Cassino manufactures toys. Pop. (2006 est.) mun., 32,603.