[3] The castle was erected there in the early Middle Ages, and enlarged later by the bishops of Fermo, who had several conflicts with the people.

The Pope decreed that it should have a cathedral Chapter, composed of two dignities (the Archpriest and the Archdeacon) and twelve Canons.

On 3 October 1571, Pope Pius named as its first bishop Lucio Sassi,[5] who became a cardinal more than twenty years later.

[15] The diocese, at first directly subject to the Holy See, has been a suffragan see of the Roman Catholic Archdiocese of Fermo since 1680.

[18] 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.

[19] These considerations applied to Montalto and to Ripatransone as the population migrated in the post-war period to jobs on the coast at San Benedetto.

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.

There was to be only one diocesan Tribunal, in San Benedetto del Tronto, and likewise one seminary, one College of Consultors, and one Priests' Council.