Ivan IV ordered the church that became Saint Basil's Cathedral built on Red Square to commemorate two military victories, the capture of the Khanates of Kazan in 1552 and Astrakhan shortly after, campaigns that extended Muscovite control deep into formerly independent Tatar territory. Construction ran from 1555 to 1561, and what resulted was not a single church in the ordinary sense but a cluster of nine separate chapels, each dedicated to a saint or feast tied to the campaign, arranged around a tall central church and unified externally by a skyline of onion domes, no two decorated quite alike.
The building's formal name, the Cathedral of the Intercession of the Most Holy Theotokos on the Moat, refers to the moat that once ran along the Kremlin wall and to the feast on which Kazan fell. Almost nobody uses that name in practice. The cathedral is known instead for Vasily the Blessed, a Muscovite holy fool revered for feigned madness adopted as ascetic humility, buried at the site with his relics later enshrined in an added chapel.
The cathedral survived threats that removed many of Moscow's other historic buildings. Napoleon's retreating army reportedly considered destroying it in 1812, and Soviet authorities are said to have discussed demolishing it in the 1930s. It was secularized into a state museum after the Russian Revolution, with occasional Orthodox services permitted rather than resumed as a working parish church.
Saint Basil's forms part of the Kremlin and Red Square, inscribed together as a UNESCO World Heritage Site in 1990, and its silhouette has become one of the most widely reproduced images of any religious building anywhere, an outcome its builders could hardly have anticipated for what was, in its own century, simply a victory church.