Site of the Roman town of Casinum, it is widely known for its abbey, the first house of the Benedictine Order, having been established by Benedict of Nursia himself around 529. It was for the community of Monte Cassino that the Rule of Saint Benedict was composed.

55,000 allied soldiers lost their lives in the Battle of Monte Cassino. On the German side, the losses were much smaller: 20,000 soldiers died.