The Cathedral of Christ the Saviour ( Хра́м Христа́ Спаси́теля ) is the tallest Eastern Orthodox Church in the world. It is situated in Moscow, on the bank of the Moskva River, a few blocks west of the Kremlin.
When the last of Napoleon's soldiers left Moscow, Tsar Alexander I signed a manifesto, December 25, 1812, declaring his intention to build a Cathedral in honor of Christ the Saviour "to signify Our gratitude to Divine Providence for saving Russia from the doom that overshadowed Her" and as a memorial to the sacrifices of the Russian people.
It took some time for actual work on the projected cathedral to get started. The first finished architectural project by architect Alexander Vitberg was endorsed by Alexander I in 1817. It was a flamboyant Neoclassical design full of Freemasonic symbolism. Construction work was begun on the Sparrow Hills, the highest point in Moscow, but the site proved insecure.
In the meantime Alexander I was succeeded by his brother Nicholas. Profoundly Orthodox and patriotic, the new Tsar disliked the Neoclassicism and Freemasonry of the project selected by his brother. He commissioned his favourite architect Konstantin Thon to create a new design, taking as his model Hagia Sophia in Constantinople. Thon's Neo-Byzantine design was approved in 1832, and a new site, closer to the Moscow Kremlin, was chosen by the Tsar in 1837. A convent and church on the site had to be relocated, so that the cornerstone was not laid until 1839.