It was founded, apparently, in the VII century at the time of the first influx of refugees from the mainland, dedicated first to Santa Maria; it was only after 1125 that the title of san Donato was added when the body of the Saint was brought from Cephalonia. The external work of the Apse is unusual; it is on a hexagonal plan with sham arcadings with niches and double columns with a gallery with arches running round above. The main facade is of typical plain basilican form of Ravennate origin. The interior is of basilican plain with nave and side aisles, with five columns down each side of Greek marble and Veneto-byzantine style capitals, with niello decirations. The bell-tower is a square tower in three sections in the characteristic shape with shallow pilasters and little arches, of the XII-XIII century Veneto-byzantine construction: the Belfry with triple windows and a crowning of little arches; the conical point is missing from steeple.