A number of khans ruled Crimea in the period from 1648 to 1676: Islam Girai III (1644-1654), Mehmed Girai IV (1654-1666), Adil Girai (1666-1671) and Selim Girai (1671-1677/78 and 1684-1691). At the start of this period, the Tatars were an enemy of the Polish-Lithuanian Commonwealth, later they fought as allies and by the end they were again an enemy.
Although the Crimea was under Ottoman protection, for much of the seventeenth century it set its own agenda. Since the Khanate relied on the collection of slaves from Ukraine, Tatar policy focused on not allowing one individual group to dominate Ukraine. If any one group became too powerful, they would shift their allegiance and “betray” their allies, sometimes even in the middle of a battle.
In the years 1648-1654 the Khanate generally supported Chmielnicki and the Cossacks. This enabled them to win many spectacular victories over the Polish army (e.g. Korsuń, Zborów, Batoh). After the Cossacks signed an alliance with Moscow the situation changed fundamentally. Afraid of the growing power of Moscow the Tatars allied themselves with the Polish-Lithuanian Commonwealth and in 1655 the Tatars fought along side of the Poles against the Cossacks and Muscovite forces. Continuing this policy Khan Mehmed Girai IV sent reinforcements for Jan Kazimierz against the Swedes. In the years 1656-1657 Crimean reinforcements fought alongside Polish forces against the Swedes and Prince Rákóczi. In 1659 Tatars supported Hetman Ivan Vyhovsky and contributed to the Muscovite defeat at Konotop (1659). Tatars also supported Poles in the campaigns of early 1660’s.
Mehmed Girai IV was regarded as a faithful ally of the Polish-Lithuanian Commonwealth, but in 1666 he was overthrown and the Ottomans took on a more direct policy in Ukraine. This led to resuming of Tatar raids into Poland and an alliance between the Cossacks and the Ottomans. In the 1670s, Khan Selim I Girai (Girej) was considered to be an outstanding military commander and an astute politician, but when the Turks put Adil Girai, their obedient vassal, on the throne in Bakhchisaray in 1666, the international significance of Crimea decreased substantially.
System of power and administration in the Crimean Khanate was based on Islamic law, Tatar tradition and regulations of Ottoman law. Modern historians and researchers emphasize Khanate was a “military state” where most of the men were obliged to military service. A khan from the Girai family was the ruler of the country and the positions of khan’s deputies were reserved for the Girai family. Kalga Sultan – usually the brother or the eldest son of the khan – was governor of the khan and managed the right (Eastern) part of the state, and Nuredin Sultan was the second governor and managed the left (Western) part.
In mid 17th century the administration of the Khanate was greatly developed and the power of the khan was strengthened. During the reign of Islam III and Mehmed IV the international position of Crimea was very high, and thanks to military expeditions income of the state increased substantially. Most profits were made on slave trade. For that reason Tatar forces always took prisoners, even within allied territories. This was felt by the Polish-Lithuanian Commonwealth on many occasions. As a result of this Polish command assigned able officers and cavalry units to “accompany” auxiliary Tatar forces.