The thirteen-year struggle over control of Ukraine included an attempted formal union of Ukraine with the Commonwealth as an equal partner (1658) and Polish military successes in 1660–1662. This was not enough to keep eastern Ukraine. Under the pressure of continuing Ukrainian unrest and the threat of a Turkish-Tatar intervention, the Commonwealth and Russia signed in 1667 an agreement in the village of Andrusovo near Smolensk, according to which eastern Ukraine (left bank of the Dnieper River) now belonged to Russia. Kiev was also leased to Russia for two years, but never returned and eventually Poland recognized Russian control of the city.