St. Mark's Basilica was originally built in the 9th century under the Doge Giovanni I. Particiaco as the final resting place for St. Mark the Evangelist, whose remains were smuggled from Egypt to Venice. In 976 the church fell victim to a fire that was started by rioters in the Doge's Palace. Today's St. Mark's Basilica was built between 1063-1094 under the Doge Pietro Orseolo and was redesigned several times until 1617. A legend says that the remains of St. Mark lost in the fire were miraculously found on June 25, 1094 - this day has been considered a "Inventio Sancti Marci" holiday ever since. Until the end of the Republic of Venice in 1797, St. Mark's Basilica was the central state shrine and private chapel of the Doge - since 1807 it has been the church of the Venetian patriarch.
A Greek cross forms the floor plan of St. Mark's Basilica (76.5 m long and 62.6 m wide), the western arm of which is slightly longer and wider. The cross is arched by a total of five magnificent domes, two of them larger than the other three. On its southern side, St. Mark's Basilica also borders the Doge's Palace, which served as the seat of government. Due to the close connection between the two commercial centers of Venice and Byzantium, the artists mostly worked in the Byzantine style, so that the Apostle Church of Constantinople, which no longer exists today, could have served as a model. The lobby, which was added between 1231-1253, clearly shows this connection, while the 14th century extensions were already built in Gothic style.
The elaborately designed facade of St. Mark's Basilica is divided into two floors and five portals with arches decorated with mosaic. The northern Porta Sant'Alipio is particularly impressive, showing an image of St. Mark's Basilica from the 13th century. The St. Mark's Lion can also be seen on the facade, because it is located in the gable field of the middle, larger arch. He was the symbol for the evangelist Mark and still today for the city of Venice, whose coat of arms he adorns. In addition, the facade is adorned with plenty of marble, countless columns made of jasper, serpentine and alabaster as well as sculptures of all kinds testify to the high representation of the building.
The gilded bronze horses of San Marco are part of a quadriga, and were about to be melted down before people became aware of their meaning. They were found originally on the triumphal arch of Emperor Nero in Rome. Today copies of these pieces of loot from Constantinople adorn the gallery on the upper floor of St. Mark's Basilica, because after their restoration in the 1960s they were exhibited in the Marciano Museum. It could be seen that the gold cover was scratched a long time ago to prevent excessive glare in the sun and to give a lifelike impression. In addition, contrary to what was assumed, the horses were not made of bronze, but mostly of copper, since it is easier to gold-plate. During the restoration, the horse statues were also incorrectly assembled so that their heads do not point outwards as originally, but towards each other.
Impressive, shiny and imposing mosaics adorn the interior of the church - from the ceiling to the floor. Overall, they cover an area of more than 8000 m² and are therefore considered one of the largest connected mosaics in the world. The hall is divided by four large pillars and six columns, creating three ships. The actual building substance of San Marco is brick on which one or two layers of cement slurry have been applied. A colored sketch of the planned scene was placed on the still wet plaster, after which the individual mosaic stones (tessarae) were pressed into the mortar by two thirds of their height. Instead of colored stones like in antiquity, the “tessarae” plates were made of colored glassflow. In some cases, gold and silver foils were melted into colorless glass and inserted with different angles of inclination in order to bring the play with light and its reflections to life.
In recent years Venice had to deal with floods many times. In November 2019, the water even rose to 1.87 meters - the highest mark since 1966. The crypt was flooded, which led to static problems and the numerous mosaics and the masonry are also attacked by the salt water. Therefore it is planned to protect the St. Mark's Basilica with a 1.20 high ring made of glass plates and thus protect it against flooding up to a flood level of two meters above normal.