The church of Saint Mark (Agios Markos), dedicated to the patron saint of Venice, used to be the official Venetian church of the city of Candia, and its construction began in 1239.
It is a three-aisled Basilica with a wooden roof and a portico at the western side, where the entrance from the side of the Morosini fountain square was located, and it had an impressive bell tower.
The Turks destroyed the frescoes of the church when they took the city; they also demolished the bell tower, built a minaret in its place, and transformed the church into a mosque. After 1956, the church was restored from damages suffered in previous years, and was used as a cultural events venue.
Nowadays it houses the Heraklion Municipal Art Gallery, where works of contemporary Cretan artists can be seen.