Ivan dispossessed Novgorod of more than four-fifths of its land, keeping half for himself and giving the other half to his allies. Subsequent revolts (1479–1488) were punished by the removal en masse of the richest and most ancient families of Novgorod to Moscow, Vyatka, and other north-eastern Rus' cities. The rival republic of Pskov owed the continuance of its own political existence to the readiness with which it assisted Ivan against its ancient enemy. The other principalities were eventually absorbed by conquest, purchase, or marriage contract: The Principality of Yaroslavl in 1463, Rostov in 1474, Tver in 1485, and Vyatka 1489.