Saint Isaac’s Cathedral is an outstanding example of late classicism, in which new movements (neo-Renaissance, Byzantine style, eclecticism) had already been manifested. It is also a unique architectural object and a high-rise dominating structure of the central part of the city.

The Cathedral owes its emergence to Peter I. Peter was born on May, 30th, on the feast day of Isaac of Dalmatia, a canonized Byzantine monk. It was decided to build a temple at the Admiralty in honour of this saint. It was decided to convert the former Admiralty drawing office into the new church. In the summer of 1707, a small wooden house with ten mica windows was built south of the shipyard. It was here that Peter I married his wife Catherine on February 19th, 1712.

The height of the cathedral is 101.5 meters, its length and width – about 100 meters. The outer diameter of the dome is 25.8 meters. The building is decorated with 112 monolithic granite columns of different sizes. The walls are lined with light grey Ruskeala marble.

Wooden constructions designed by engineer A. Betancourt were used in column installation. One of the porticos’ friezes features a sculptural image of the architect Montferrand.

The phrase placed in the frieze of the northern portico – “In thy strength, O Lord, the king shall joy”, – can be considered the expression of the whole building’s idea.

The statues, located on the corners and peaks of the pediments, represent the 12 Holy Apostles (sculptor I. Vitali) – the closest disciples of Jesus Christ – with the tops crowned with statues of evangelists (the authors of Gospels – the first four books of the New Testament, which recount the teachings and life of Jesus Christ).