In the bull "Dominici Gregis", of 1 September 1824, Pope Leo XII states that the diocese of Sarsina had existed since the 5th century.
[7] Bishop Angelo Peruzzi (1581–1600) had the castle decorated with effigies of his predecessors, to each of which was affixed a short verse, giving no dates and generally vague as to episcopal accomplishments.
[8] Bishop Giovanni Battista Braschi (1699–1718) reported in his Relatio of 1704 that the cathedral had once had a Chapter with three dignities (the Provost, the Archdeacon, and the Archpriest), but that the Archdeaconry survived.
[10] In 1807 Napoleon, who was President of the Cisalpine Republic, suppressed the diocese, in accordance with policies originally established by the French Civil Constitution of the Clergy.
The Second Vatican Council (1962–1965), in order to ensure that all Catholics received proper spiritual attention, decreed the reorganization of the diocesan structure of Italy and the consolidation of small and struggling dioceses.
Based on the revisions, a set of Normae was issued on 15 November 1984, which was accompanied in the next year, on 3 June 1985, by enabling legislation.
According to the agreement, the practice of having one bishop govern two separate dioceses at the same time, aeque personaliter, was abolished.