The Senate commissioned for the clock to be built in 1493 because the old clock of Sant'Alipio was deteriorating.  Zuan Carlo Rainieri was tasked with creating the clock. Planning was time-consuming, and construction did not begin until a few years later. Though the image is from another turret clock in Venice, it dates back to 1500, which makes it approximately the same age as the St. Mark's Clock Tower. Image By Didier Descouens (Own work) [CC BY-SA 4.0 (http://creativecommons.org/licenses/by-sa/4.0)], via Wikimedia Commons