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 can be identified with Paleocastro, which appears in Notitia III of the Diatiposi of Leo VI the Philosopher (886-901). The name S. appears only in Latin sources and not in very ancient times. It is indeed doubtful whether the bishop Cerentino, who subscribed to the Third Lateran Council of 1179, belongs to this see. Among its successors worthy of note are: Peter (1254-82), formerly abbot of S. Euphemia, who frequently appears in the Register of Alexander IV; Peter Vicedomini (1330-1338), also a Benedictine, whose election was confirmed by John XXII despite the opposition of the metropolitan; the Franciscan Thomas De Rose (1342-51), a man of great learning; Cardinal Girolamo Grimaldi (1534-35), Thomas Orsini (1566-67), and above all the Dominican Timoteo Giustiniani (1568-71), who invited his brethren to the city.
The diocese of S., very small and mountainous, had no possibility of development. In 1818 Pius VII suppressed it, uniting its territory to that of Cerenzia-Carati, which remained the sole suffragan of S. Severina.