Kievan Rus′ was not able to maintain its position as a powerful and prosperous state, in part because of the amalgamation of disparate lands under the control of a ruling clan. As the members of that clan became more numerous, they identified themselves with regional interests rather than with the larger patrimony. Thus, the princes fought among themselves, frequently forming alliances with outside groups such as the Polovtsians, Poles, and Hungarians. During the years from 1054 to 1224 no less than 64 principalities had a more or less ephemeral existence, 293 princes put forward succession claims, and their disputes led to 83 civil wars.
The Crusades brought a shift in European trade routes that accelerated the decline of Kievan Rus′. In 1204 the forces of the Fourth Crusade sacked Constantinople, making the Dnieper trade route marginal. As it declined, Kievan Rus′ splintered into many principalities and several large regional centers: Novgorod, Vladimir-Suzdal, Halych, Polotsk, Smolensk, Chernigov (modern Chernihiv), and Pereyaslav. The inhabitants of those regional centers then evolved into three nationalities: Ukrainians in the southeast and southwest, Belarusians in the northwest, and Russians in the north and northeast.