Zalesye

In the twelfth century, this fertile area, being well protected from Turkic incursions by the forests, provided a favourable oasis for Slavic people migrating from the southern borders of Kievan Rus.

The population of the area rapidly increased and by 1124 reached the point when Yuri Dolgoruki found it expedient to move his princely seat from Rostov in the Upper Volga Region to Suzdal in Zalesye.

Yuri established other important urban centres in Pereslavl-Zalessky (founded 1152), Yuriev-Polsky (1152), Dmitrov (1154), Starodub-on-the-Klyazma (1152), Vladimir-Zalessky (1108), Ksnyatin (1136), and Yaropolch-Zalessky (1136).

His unexpected death (1157) forestalled this plan, but Yuri's son Andrew the Pious finally moved the princely seat to another young town, Vladimir, in 1157.

During the Mongol invasion of Kievan Rus' (1223–1240), when the woods were gradually being cleared and new centres developed in Moscow, Tver, and elsewhere, the strategic importance of Zalesye declined.