Architecture of Kievan Rus'

The medieval state of Kievan Rus' incorporated parts of what is now modern Ukraine, Russia, and Belarus, and was centered on Kiev and Novgorod. Its architectural style quickly established itself after the adoption of Christianity in 988 and was strongly influenced by the Byzantine. After the disintegration of Kievan Rus' followed by Mongol invasion in the first half of the 13th century, the architectural tradition continued in the principalities of Novgorod, Vladimir-Suzdal, Galicia-Volhynia and eventually had direct influence on the Russian, Ukrainian, and Belarusian Architecture.

The great churches of Kievan Rus', built after the adoption of Christianity in 988, were the first examples of monumental architecture in the East Slavic lands. The architectural style of the Kievan state which quickly established itself was strongly influenced by the Byzantine. Early Eastern Orthodox churches were mainly made of wood with the simplest form of church becoming known as a cell church. Major cathedrals often featured scores of small domes, which led some art historians to take this as an indication of what the pagan Slavic temples should have looked like.

The 10th-century Church of the Tithes in Kiev was the first cult building to be made of stone. The earliest Kievan churches were built and decorated with frescoes and mosaics by Byzantine masters.

...
Wikipedia