The Crimean-Nogai raids were slave raids carried out by the Khanate of Crimea and by the Nogai Horde into the region of Rus' then controlled by the Grand Duchy of Moscow , by the Tsardom of Russia , by the Russian Empire  and by the Grand Duchy of Lithuania . These raids began after Crimea became independent about 1441 and lasted until the peninsula came under Russian control in 1774. Their main purpose was the capture of slaves, most of whom were exported to the Ottoman slave markets in Constantinople or elsewhere in the Middle East. The raids were an important drain of the human and economic resources of eastern Europe. They largely inhabited the settlement of the "Wild Fields" - the steppe and forest-steppe land which extends from a hundred or so miles south of Moscow to the Black Sea and which now contains most of the Russian and Ukrainian population. The raids also played an important role in the development of the Cossacks. Estimates of the number of people involved vary: according to Alan W. Fisher  the number of people deported from the Slavic lands on both sides of the border during the 14th to 17th centuries was about 3 million. Michael Khodarkhovsky estimates that 150,000 to 200,000 people were abducted from Russia in the first 50 years of the 17th century. The ﬁrst major Tatar raid for slaves occured in 1468 and was directed into Galicia. Crimean Khan Devlet I Giray even managed to burn down Moscow during the 1571 campaign. The last raid into Hungary by the Crimean Tatars took place in 1717. In 1769 a last major Tatar raid, which took place during the Russo-Turkish War, saw the capture of 20,000 slaves.
Question: How many factions controlled the region of Rus'?
Answer: 4