The Cathédrale Sainte-Marie de Bastia stands within the citadel quarter, a short walk from the Musée de Bastia. The building dates primarily from the 15th century, though the baroque interior was completed during extensive works in the 17th and 18th centuries. It served as the seat of the Bishop of Mariana et Accia until Napoleon, born in Ajaccio, reorganised the church hierarchy and transferred the bishopric to his native city.
The cathedral's most celebrated possession is the processional silver statue of the Assumption, a large and technically impressive work made in Genoa in 1748. The statue is carried through the citadel and upper town in a procession on the Feast of the Assumption each August — one of Bastia's major annual events. The interior also contains several good baroque paintings and an ornate organ. The cathedral is usually open to visitors during the day.