Chronology of Catholic Dioceses:Notes on the Diocese of Mariana

The diocese of Mariana was founded in the 5th century. It was part of the ecclesial province of Pisa from 1092, and then of the province of Genova from 1130. relevant directement du Saint-Siège puis de Pise en 1092 et de Gênes en 1130. The bishop resided in Bastia from 1570. In 1790, revolutionary France made Bastia the sole Corsica diocese, a move that was not recognized by Rome. The Corsican bishops all escaped to Italy, as they refused to sign the civil Oath. In 1801, the diocese of Mariana was suppressed by Rome and incorporated it in the diocese of Ajaccio, which was restored that same year.

In April 2002, the suppressed dioceses of Aleria, Mariana, Nebbio, and Sagone, were designated titular sees by the Congregation of Bishops.

-CT (information from Charles N. Bransom, http://www.culture.fr/culture/inventai/itiinv/cathedrale/cat_corse.html )