Finally, the Pope wrote to Charles Emmanuel I, Duke of Savoy, officially notifying him of the creation of the diocese and the appointment of Bishop Daddeo.

In fact, the initiative for the creation of the new diocese had come from Charles Emanuel himself, who had recently (1588) seized the Marqisate of Saluzzo in an effort to free himself from the political grasp of his French cousins.

[4] During the occupation by the French Republic, between 1802 and 1805, Piedmont was annexed to metropolitan France, and divided into six departments: Ivrea or Doire (Dora), Marengo, Po or Eridan, Sofia, Stura, and Tanaro.

As in metropolitan France, the government program also included reducing the number of bishoprics, making them conform as far as possible with the civil administration's "departments".

In accordance with the Concordat of 1801, and at the demand of the First Consul N. Bonaparte, Pope Pius VII was compelled to issue a bull, Gravissimis causis (1 June 1803),[6] in which the number of diocese in Piedmont was reduced from seventeen to eight: Turin, Vercelli, Ivrea, Acqui, Asti, Mondovi, Alessandria and Saluzzo.

The details of the new geographical divisions were left in the hands of Cardinal Giovanni Battista Caprara, the Papal Legate in Paris.

The ancient Collegiate Church of the Virgin Mary and Saint Juvenalis, the largest in the town of Fossano, was presided over by a Provost a Penitentiarius and ten canons.

It was chosen as the new cathedral on the same day as the town was promoted to the rank of city (civitas) by Pope Clement VIII, 15 April 1592.