STRONGOLI. - It was one of the five tiny dioceses on the Ionian side of Calabria, established by the Byzantines around the middle of the 9th century for the metropolitan see of S. Severina, created ex novo together with its suffragans.
It seems that S. is the heir of Petilia Policastro, and it is therefore more than probable that it may be identified with the Paleocastro occurring in Notitia III of the Diatiposi of Leo VI the Philosopher (886–901). Under the designation S. it appears only in Latin sources and in a not very ancient period. Indeed, it is doubtful whether Bishop Cerentino, who subscribed at the Lateran Council of 1179, belonged to this see. Among his successors, worthy of note are: Pietro (1254–82), formerly abbot of S. Eufemia, who frequently occurs in the Regesto of Alessandro IV; Pietro Vicedomini (1330–1338), likewise a Benedictine, whose election was confirmed by Giovanni XXII despite the opposition of the metropolitan; the Franciscan Tommaso De Rose (1342–51), a man of great learning; Cardinal Girolamo Grimaldi (1534–35), Tommaso Orsini (1566–67), and above all the Dominican Timoteo Giustiniani (1568–71), who summoned his fellow brethren to the city.
The diocese of S., very small and mountainous, had no possibility of development. In 1818 Pio VII suppressed it, annexing its territory to that of Cerenzia-Cariati, which remained the sole suffragan of S. Severina.