In next year a full war with the Ottoman Empire was close (according to one source, the sultan created a huge army, while according to others, it was close to being formed); however the sultan suffered from another failure: his vassal, khan of Crimea Canibek Giray (also known as Janibek or Dzhanibek), had decided to attack Muscovy. Muscovite troops were fighting with Polish troops, then-Polish Ukraine was bolstered by Cossacks and Koniecpolski's troops, and many times Tatars themselves offered to the Commonwealth to raid Muscovy in exchange for “gifts” (or were sent “gifts” to do so). An army of Tatars, approximately 20,000 strong, attacked Muscovy in 1632, and again in 1633 in even larger numbers. Attacks continued until 1637. In June 1634, Tatars operated in the area of Kursk, Orel, and Mtsensk. A year later they attacked the Lesser Nogai Horde and Azov Horde. In 1636 Crimean Tatars attacked again and the Greater Nogai horde changed their allegiance to Crimea. The southern defenses were destroyed and the country was depopulated (the number of jasyr captives sold in Crimea is estimated at 10,000). Russian historians accuse the Poles of coordinating their attacks with those of Tatars.