RE:RE:RE:RE:RE:RE:Hey FOGhead, are you bothering these people In 882, Rurik's successor Prince Oleg, who was, actually, playing the role of regent at Rurik's young son because Rurik had died by that time, came to Kiev. He ousted two brothers who, apparently, had once been members of Rurik's squad. So, Russia began to develop with two centers of power, Kiev and Novgorod.
The next, very significant date in the history of Russia, was 988. This was the Baptism of Russia, when Prince Vladimir, the great-grandson of Rurik, baptized Russia and adopted Orthodoxy, or Eastern Christianity. From this time the centralized Russian state began to strengthen. Why? Because of a single territory, integrated economic ties, one and the same language and, after the Baptism of Russia, the same faith and rule of the Prince. The centralized Russian state began to take shape.
Back in the Middle Ages, Prince Yaroslav the Wise introduced the order of succession to the throne, but after he passed away, it became complicated for various reasons. The throne was passed not directly from father to eldest son, but from the prince who had passed away to his brother, then to his sons in different lines. All this led to the fragmentation and the end of Rus as a single state. There was nothing special about it, the same was happening then in Europe. But the fragmented Russian state became an easy prey to the empire created earlier by Genghis Khan.