Throughout the Middle Ages, Russia's most important buildings followed Byzantine patterns, inspired by the architecture of Constantinople (now Istanbul in Turkey) and the eastern Roman Empire. The plan for Russia's churches was that of a Greek cross, with four equal wings. Walls were high with few openings. Steep roofs were topped with a multitude of domes. During the Renaissance, however, Byzantine ideas mingled with classical themes.
When Ivan III established a unified Russian state, he asked the celebrated Italian architect, Alberti (also known as Aristotle) Fioravanti, to design a grand new cathedral for Moscow. Built on the site of a modest church erected by Ivan I, the new Assumption Cathedral combined traditional Russian Orthodox building techniques with ideas from the Italian Renaissance.
The cathedral was constructed of plain gray limestone, without ornamentation. At the summit are five golden onion domes designed by Russian masters. The interior of the cathedral is lavishly decorated with more than a 100 statues and multiple tiers of icons. The new cathedral was completed in 1479.