that article is a long winded way of rehashing the old Tzarist claim that the Russian Empire was the inheritor of the Byzantines, a self-styled "Third Rome".
Putin simply sees himself as the new Tzar, and by extension master of the lands of the Third Rome, i.e. the Baltics, Ukraine, et al.
Putin simply sees himself as the new Tzar, and by extension master of the lands of the Third Rome, i.e. the Baltics, Ukraine, et al.