St Mark's Basilica – Wikipedia
The Patriarchal Cathedral Basilica of Saint Mark (Italian: Basilica Cattedrale Patriarcale di San Marco), commonly known as Saint Mark’s Basilica (Italian: Basilica di San Marco; Venetian: Baxéłega de San Marco), is the cathedral church of the Roman Catholic Archdiocese of Venice, northern Italy. It is the most famous of the city’s churches and one of the best known examples of Italo-Byzantine architecture. It lies at the eastern end of the Piazza San Marco, adjacent and connected to the Doge’s Palace. Originally it was the chapel of the Doge, and has been the city’s cathedral only since 1807, when it became the seat of the Patriarch of Venice, archbishop of the Roman Catholic Archdiocese of Venice, formerly at San Pietro di Castello.