Definition of "sultanry"

Neither should I make any great difficulty to affirm the same of the sultanry of the Mamalukes ; where slaves , and none but slaves , bought for money , and of unknown descent , reigned over families of freemen

a. 1627 (date written), Francis [Bacon], “Considerations Touching a VVarre vvith Spaine. […]”, in William Rawley, editor, Certaine Miscellany VVorks of the Right Honourable Francis Lo. Verulam, Viscount S. Alban. […], London: […] I. Hauiland for Humphrey Robinson, […], published 1629