This was the first monastery set up by St Benedict, and the only one remaining today. Much of what can be seen today is from the 9th century onwards including some marvellous 12th cloisters and frescos. Sadly the gothic church that they had they decided to build a classical church inside, which is what can be seen today. The 30m tall bell tower and is rather splendid with Romanesque features. I rather enjoyed the trompe l’oeil cloister and the moving eyes of St Matthew from around 13/14th C frescoes which is certainly the oldest version of that trick I have come across.