CISSA. – This small city of Istria, situated on an island a short distance from the present-day city of Rovigno, was the seat of a purple-dye manufactory subject to the imperial monopoly. It appears as an episcopal see at the end of the 6th century, during the schism of the Three Chapters; it disappeared after the end of the 7th century, though it is not known exactly when, following a seismic event in which the city itself was swallowed by the sea.
BIBL.: F. Babudri, Il vescovado di C. in Istria, in Memorie della Società istriana di archeologia, ecc., 31 (1919), p. 35 ff. Pio Paschini