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.
The church is located on the eastern end of Saint Mark's Square, the former political and religious centre of the Republic of Venice, and is attached to the Doge's Palace. Prior to the fall of the republic in 1797, it was the chapel of the Doge and was subject to his jurisdiction, with the concurrence of the procurators of Saint Mark de supra for administrative and financial affairs.
The present structure is the third church, begun probably in 1063 to express Venice's growing civic consciousness and pride. Like the two earlier churches, its model was the sixth-century Church of the Holy Apostles in Constantinople, although accommodations were made to adapt the design to the limitations of the physical site and to meet the specific needs of Venetian state ceremonies. Middle-Byzantine, Romanesque, and Islamic influences are also evident, and Gothic elements were later incorporated. To convey the republic's wealth and power, the original brick façades and interior walls were embellished over time with precious stones and rare marbles, primarily in the thirteenth century. Many of the columns, reliefs, and sculptures were spoils stripped from the churches, palaces, and public monuments of Constantinople as a result of the Venetian participation in the Fourth Crusade. Among the plundered artefacts brought back to Venice were the four ancient bronze horses that were placed prominently over the entry.
The interior of the domes, the vaults, and the upper walls were slowly covered with gold-ground mosaics depicting saints, prophets, and biblical scenes. Many of these mosaics were later retouched or remade as artistic tastes changed and damaged mosaics had to be replaced, such that the mosaics represent eight hundred years of artistic styles. Some of them derive from traditional Byzantine representations and are masterworks of Medieval art; others are based on preparatory drawings made by prominent Renaissance artists from Venice and Florence, including Paolo Veronese, Tintoretto, Titian, Paolo Uccello, and Andrea del Castagno.
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