The Cathedral of the Protection of Most Holy Theotokos on the Moat, popularly known as Saint Basil's Cathedral, is a Russian Orthodox church erected on the Red Square in Moscow in 1555–61. Built on the order of Ivan the Terrible to commemorate the capture of Kazan and Astrakhan, it marks the geometric centre of the city and the hub of its growth since the 14th century. It was the tallest building in Moscow until the completion of the Ivan the Great Bell Tower in 1600.
The original building, known as "Trinity Church" and later "Trinity Cathedral", contained eight side churches arranged around the ninth, central church of Intercession; the tenth church was erected in 1588 over the grave of venerated local saint Vasily (Basil). In the 16th and 17th centuries the church, perceived as the earthly symbol of the Heavenly City, as happens to all churches in Byzantine Christianity, was popularly known as the "Jerusalem" and served as an allegory of the Jerusalem Temple in the annual Palm Sunday parade attended by the Patriarch of Moscow and the tsar. The building's design, shaped as a flame of a bonfire rising into the sky, has no analogues in Russian architecture: "It is like no other Russian building. Nothing similar can be found in the entire millennium of Byzantine tradition from the fifth to fifteenth century ... a strangeness that astonishes by its unexpectedness, complexity and dazzling interleaving of the manifold details of its design." The cathedral foreshadowed the climax of Russian national architecture in the 17th century. Under the Soviet Union the church was re-purposed and has operated as a division of the State Historical Museum since 1928. It was completely secularized in 1929 and, as of 2011, remains a federal property of the Russian Federation. The church has been part of the Moscow Kremlin and Red Square UNESCO World Heritage Site since 1990.
It is often mislabelled as the Kremlin owing to its location on Red Square in immediate proximity of the Kremlin. This extremely pretty card was sent to me by Alena.