The author discusses information about newly built churches and fortresses in Russia, as well as repair works in the existing structures in the second half of the thirteenth - first third of the fourteenth centuries. He suggests that the Mongol invasion was, perhaps, a major but not the only factor that caused uneven development of the early Russian architecture in the studied period. It was a hard time in the Old Rus', and building new churches and fortresses was difficult due to the scarcity of available funds, high taxes imposed by the Horde, ongoing feuds between knyazes and lack of qualified masters. Nevertheless, the time was marked by development of architecture and, even more, it laid the foundation for further evolution of the early Russian architecture.