In the southwest corner next to the church there was a high bell tower with a clock, which stood taller than any other building in the town. Throughout the long siege of the city by the Turks, the bell tower gave the warning signal during cannon bombardment, and was thus often targeted by enemy fire.

Marinos Tzane Bounialis relates the following: "... He [the enemy] would never lay off firing cannon volleys at the bell towers and at every great house, at the church and bell tower of St. Mark, so as to break its bell, which was its end - when war was being waged it would sound, the people would hear the enemy were descending and would all run [for cover] together."