The Patriarchal Cathedral Basilica of Saint Mark (Italian: Basilica Cattedrale Patriarcale di San Marco), commonly known as St Mark's Basilica (Italian: Basilica di San Marco; Venetian: Baxéłega de San Marco), is the cathedral church of the Catholic Patriarchate of Venice; it became the episcopal seat of the Patriarch of Venice in 1807, replacing the earlier cathedral of San Pietro di Castello. It is dedicated to and holds the relics of Saint Mark the Evangelist, the patron saint of the city.
(https://en.wikipedia.org/wiki/St_Mark's_Basilica)