What were the similarities and differences in the state structure of the Frankish Empire and Ancient Russia?

The Frankish kingdom and the Old Russian state have a number of similarities and a number of differences. Both states were formed for similar reasons. They were headed by central rulers with broad powers. Both the Franks and the Slavs passed from paganism to Christianity. They were formed during the great migration of peoples. There were tendencies towards state orders in them, but the influence of tribal relations did not completely deplete. They differed in the form of adopted Christianity and in the time of their emergence.