Inhabited since ancient times because of its strategic location, this unique island in Lake Como has had its own unique history. The discovery of the remains of a building with columns under the present Church of Saint John indicates the existence of a building of considerable proportions from Roman times, perhaps a villa or a pagan temple. Towards the middle of the fifth century, Christianity had spread through the region and the Bishop of Como, Saint Abbondio, founded an oratory on the island, dedicating it to Saint Eufemia. The history of the island is distinguished at the time of the barbarian invasions in the mid-sixth century. It was on the fortified island that the Magister militum (Latin for “Master of the Soldiers”) Francione, the last Byzantine military commander, ruled for years, and held out for six months of sieges by the Longobardi of Autari before capitulating in 585.
The fortifications of the island were impressive and surrounded a village with stairs carved into the rock, buildings of masonry and a sewage system. At the time of the municipalities (eleventh and twelfth centuries), the island was an ally of the Milanese and, following their fortunes, was completely destroyed in 1169 by Frederick Barbarossa and was then no longer inhabited.