This article investigates religious nationalism in the Russian–Ukrainian conflict, which has appeared in political and popular rhetoric and has been expressed through violence. From the Tsarist era, Kyiv and Crimea have featured centrally in Russian national mythology as the cradle(s) of Russian Christianity. This nationalist conception of space persisted after political borders changed with the collapse of the Soviet Union, as has the Russian Orthodox Church's historic jurisdiction in Ukraine. As a result, Russian Orthodox believers retain a special affinity for Kyiv and Crimea, and many Ukrainian citizens have looked to Moscow for matters of faith. Subjects of inquiry include religious nationalism, the baptism of Slavic Prince Vladimir (Volodymyr), Orthodox holy places in Crimea and Ukraine, Patriarch Kirill's Russian World concept, and religious violence in Ukraine and Crimea.