Once the site of a Roman fort and medieval settlement, Lake Como's only island forms its own little bay with the mainland, just offshore from Ossuccio. When the Lombards invaded northern Italy, the island held out as a Byzantine redoubt, and slowly filled with houses and churches, the whole known as Cristopolis. They even say the Holy Grail was deposited here for a time. Purchase admission tickets from the Antiquarium; boat tickets to the island are sold separately by taxi boat and ferry operators.
The medieval settlement was razed by Como in 1169 as punishment for its loyalty to Milan. Today, as silent witness to this terrible event, lie the scant ruins of the Romanesque Chiesa di Sant'Eufemia and, next to it, the more solid remnants of the triple apse of a pre-Romanesque church at the north end of the island.