Abbazia Greca di San Nilo

Grottaferrata's fortified monastery, the last of the Byzantine-Greek abbeys that once dotted medieval Italy, was founded in 1004. The walls and battlements were added some 400 years later to provide a protective perimeter to the Chiesa di Santa Maria di Grottaferrata. This bejewelled, icon-laden church features a series of 17th-century frescoes by Domenichino (in the Cappella Farnesiana) and a revered Byzantine image of Santa Maria. Also in the abbey is a small museum charting the monastery's thousand-year-old history.