Kösem Sultan was the chief consort and legal wife of the Ottoman Sultan Ahmed I, ‘valide sultan’ as the mother of sultans Murad IV and Ibrahim, and büyük ("elder") ‘valide sultan’ as the grandmother of Sultan Mehmed IV. She often took part in the government during the reign of her husband Ahmed and later wielded unparalleled political power as regent during the early reign of her son Murad and then again during the minority of her grandson Mehmed. One of the central figures during the Sultanate of Women, she was instrumental in putting an end to the centuries-old practice of fratricide in the Ottoman Empire by convincing Ahmed to spare his brother Mustafa. She also supported enthronement of Mustafa I and retained her status and power despite her banishment during the reign of Osman II.