Just before Mehmed came to the throne, Russia allied with the rebellious Cossacks, thereby provoking the Russo-Polish War (1654–1667). Crimea switched sides, supporting the Poles against the Russians and Cossacks. The alliance was not close and Russia tried to weaken it. Poland paid the Crimeans to invade Ukraine, which they did. A Polish-Tatar army under 'Grand-general Potocki' attacked 'Ulman' or 'Human'. Russians and Cossacks came to the rescue and were defeated at 'Drischipol'. Khmelnitski bribed the Crimeans and they withdrew, laden with booty. The Cossacks raided Poland and returning, had an inconclusive conference with Mehmed on the Oserna River. In 1657 Crimea attacked George II Rákóczi of Transylvania who was attacking Poland. The Crimeans returned with several thousand cartloads of booty. Next year Crimea sacked Rakoczi's capital of Gyulafehérvár and returned with about 17000 slaves. In 1657 Khmelnitski died. Martyn Pushkar rebelled against the new pro-Polish hetman Vygotsky and drowned his envoys to Crimea in the Dnieper. Next year Poles and Tatars killed Pushkar and pillaged Poltava. In 1559 the Russians invaded and were defeated by Poles and Tatars at the great Battle of Konotop. In 1660 Poles and Crimeans defeated Russia at the Battle of Chudnov. Howorth claims that the Crimeans slaughtered 30000 prisoners. In 1661 the Tatars were again in Transylvania where they defeated John Kemény (prince) who had supported Rakoczi and now rebelled against the Turks. In 1663, according to Howorth, the Crimeans were fighting in Moravia and Silesia. In 1666 Mehmed was deposed.