 The cathedral was the seat of the Bishop of Nebbio until 1801, when the diocese was merged into the Diocese of Ajaccio.The ancient region of the Nebbio, or Nebbiu, on Corsica formed a Christian bishopric from the 5th century onwards.The former cathedral, now the church of Santa Maria Assunta, located at the edge of the town of Saint-Florent on the road that leads to Poggio d'Oletta, is a heavily-restored Romanesque structure.