Some historians claim that Ancient Petelia already was a bishopric, established perhaps in 546 or then adopting the city's new medieval name Strongoli, but without solid evidence, and the see in never mentioned in the Byzantine imperial Notitia Episcopatuum of the Patriarchate of Constantinople, which most dioceses in Calabria belonged to in the 9th till 11th centuries, so its foundation may rather date from the Normans, probably late 12th century.

The first historical record of the Diocese of Strongoli (Curiate Italian) / Strongulen(sis) (Latin adjective) is a papal bulla from Pope Lucius III in 1183, naming it among the suffragans of the Archdiocese of Santa Severina (while confirming the Metropolitan's privileges).

Its Cathedral was the Church of Peter and Paul (chiesa dei Santi Pietro e Paolo), the episcopal city's only parish.

(all Roman Rite) The diocese was nominally restored in 1969 as Titular bishopric of Strongoli (Italian) / Strongulen(sis) (Latin adjective).

It has had the following incumbents, so far of the fitting Episcopal (lowest) rank : Strongoli relies on the production of oil, wine, cereals, citruses and intensive cattle breeding.