Torcello, island-village in the Laguna Veneta (Venice Lagoon) and an eastern environ of Venice, Italy. Founded in ad 452 by refugees from Altino on the mainland, the bishopric of Altino was transferred there in the 7th century. The island, a flourishing city in ancient times, was the head of an association of the communes of the lagoon until the seat of government was moved to the Rialto in 811; the bishopric was removed to Murano. Notable landmarks are the remains of the Sta. Maria Assunta cathedral (founded 639, rebuilt 864–67 and 1008), with a 9th-century baptistery and fine Veneto-Byzantine mosaics, and the 12th-century church of Sta. Fosca. Two small 14th-century palaces house a museum. Torcello is inhabited mainly by fishermen and market gardeners.