There has been a church on this site since the early 800s when Venetian merchants stole the relics of St Mark the Evangellist from Alexandria.
During later years the church became the chapel for the Doge or elected ruler of Venice. The function of the church changed gradually in later years, becoming more of a state institution than the personal church of the Doge.
However, it was not until 1807, at the instigation of Napoleon, that the church become the seat of the Bishop of Venice and therefore the cathedral for the city. Before this time, San Pietro di Castello had been recognised as the cathedral of Venice.
The exterior of the church, consists of marble columns, mosaics and statuary, some of which was plundered from Constantinople during the Fourth Crusade.
Access to the main part of the church is free, a visit normally only lasts 30 minutes or so. Access to St. Mark's Museum, the Golden Pall and the Treasury of St. Mark's Basilica are available at the extra cost of a few euros.