In their family myth, the Princes Yusupov claimed descent from Tamerlane and the Prophet Mohammed. To explain their fabulous wealth, they claimed descent from the rulers of the Khanate of Crimea. While Wikipedia and Russian tourist guides treat this as history, the myth only gained a wider audience with the writings of Prince Felix Felixovich Yussupov in the 20th century.
Abdul Mirza was living in the Khanate of Crimea in the 17th century. The Khanate of Crimea was ruled by the Giray family which claimed descent of Genghis Khan (true or not, descent from Genghis Khan was a necessity for anyone wanting to rule a horde; even the Tsars claimed descent from Genghis Khan to keep control of the hordes forming part of their realm). While the Khan ruled the Khanate, provinces were ruled by a Bey. Under a Bey, a Mirza would rule as much as a small county or as little as a few villages.
The Khanate of Crimea was founded and recognised in 1441, and in 1449 Haci Giray took control of it as its first Khan. Expansionist politics by the Khans meant they got the attention of the Sultan of the Ottoman Empire and his army knocking on the gates of their capital. The Khan capitulated, and received in turn a pleasant surprise. They weren’t treated as a vassal state, but were acknowledged as independent rulers. Instead of having to pay tribute to the Sultan, the latter hired their cavalry for good gold.
The main income of the Khanate, though, derived from pillaging and the slave trade. Slaves were collected during raids into the lands of the Moscovy Rus and other neighbours to be sold through the seaport of Caffa to dealers from the Ottoman Empire. At the beginning of the 17th century, the weakening of the Ottoman Empire went hand in hand with the strengthening of the Khanate’s other neighbours. The country went into severe recession, and discontent with the rule of the Giray Khans set in.
Abdul Mirza’s defection to the Russians was a consequence of this development and the ongoing war between Russia and the Ottoman Empire. It was not a turning point for Russian politics, nor was it a fatal blow to the Khanate. It was only a minor noble changing sides. But still he received the title Prince Yussupov from Tsar Fyodor. Why?
Tsar Fyodor III (and not as claimed in the myth the saintly Fyodor I) spent his time in office waging war on the Ottoman Empire to gain access to the Black Sea. The Khanate of Crimea was decidedly in the way of to achieve such an access. Instant promotion for Abdul Mirza had therefore two goals: To send a message to other Khanate nobles that they would be received with honour, and to build nobility independent of the closely interrelated Boyar families at loggerheads with the Romanovs. What Abdul Mirza brought into the Empire was largely irrelevant; his first land grant ensured that he would be able to side with the tsar against Turkey, and the Boyars if necessary.
In the eyes of the established nobility, the first Prince Yusupov was a foreigner, an upstart, a social climber, and nouveaux-riche to boot. These labels would stick to the name like glue, and only the upheaval of the Russian Revolution would make them fade away. The same labels made the Yusupovs extremely loyal advisors to the Romanov tsars (upstarts after the Time of Troubles; foreigners after the death of the last Romanov Tsarina Elisabeth and the advent of the Holstein-Gottorp (Schleswig-Holstein-Gottorf) dynasty of Romanovs).