Kosem Sultan, Ottoman Valide Sultan and regent (b.1589)

Kösem Sultan (Turkish pronunciation: [cœˈsɛm suɫˈtan], Ottoman Turkish: كوسم سلطان, romanized: Kösem Sulṭān; c. 1589 – 2 September 1651) also known as Mahpeyker Sultan (Turkish pronunciation: [mahpejˈkɛɾ suɫˈtan]; from the Persian compound ماه پيكر, Māh-peyker; lit. ‘Visage of the Moon’) was Haseki Sultan of the Ottoman Empire from 1605 to 1617 as the chief consort and wife of Sultan Ahmed I (r. 1603–1617), Valide Sultan as the mother of Sultans: Murad IV (r. 1623–1640) and Ibrahim (r. 1640–1648), and Büyük Valide (Queen grandmother) of Sultan Mehmed IV (r. 1648–1687). She became one of the most powerful and influential women in Ottoman history as well as a central figure during the era known as the Sultanate of Women.Born in Tinos (then an overseas possession of the Republic of Venice, now Greece) to a Greek Orthodox priest, she was kidnapped at the age of 15 and sold as a slave by the Bosnian Beylerbey before being sent to the Imperial Harem in Constantinople. She rose to prominence early in Ahmed I's reign as part of a series of changes to the hierarchy of the Imperial Harem. As Haseki Sultan (legal wife of Ahmed I), her influence over the sultan increased in the following years, and it is said that she acted as one of his advisers. Many historians credit her with persuading Ahmed I to spare the life of his younger half-brother, Mustafa, and thereby halting the centuries-old practice of fratricide in the Ottoman Empire. After the death of Ahmed I, she was briefly banished to the Old Palace (Eski Sarayı).

Following Murad IV’s accession to the Ottoman throne in 1623, Kösem was thrust into the political arena, becoming the first official female regent (naib-i-sultanat) of the Ottoman Empire. As regent, she rose to immense notoriety and affection among her subjects and wielded extraordinary political power in the Ottoman Empire. Despite her son's opposition, she remained active in certain politics and court affairs even after being forced to step down as regent in 1632, and continued to attend divan (cabinet) meetings from behind a curtain. Following Murad IV’s death in 1640, she was re-appointed regent for her incompetent son, Ibrahim. She sought to rule in his place by encouraging Ibrahim to entertain himself with his concubines. In 1647, she attempted, with the support of the Grand Vizier Salih Pasha and other prominent Ottoman officials, to overthrow Ibrahim in favor of his eldest son, Mehmed, but she was unsuccessful. She gave her consent to Ibrahim's execution when a coup d'état erupted against him in 1648. Kösem was named regent for the third time for her grandson, Mehmed IV. However, Turhan Sultan, her daughter-in-law, began to assert what she saw to be her legitimate authority. As a response, Kösem plotted to overthrow Mehmed IV in favour of his younger half-brother, Suleiman, which culminated in her assassination in 1651. She was buried in the mausoleum of her husband Ahmed I in Sultan Ahmed Mosque.

The brutal assassination of Kösem Sultan caused tumult and rioting in Constantinople and resulted in the execution of hundreds of men. For over 35 years, she had been at the epicentre of political power in the Ottoman Empire. Many historians disagreed on her motivations for supporting the Janissaries’ cause during her time as regent. Some believed she had gained a large wealth through unlawful methods and that her involvement in state affairs was to be reprimanded. She was, however, a renowned benefactress who put the money from the lands and incomes she earned to good use, undertaking charitable works and construction projects as tangible indications of the dynasty's concern for its subjects. After her death, she was referred to by the names: "Vālide-i Muazzama" (magnificent mother), "Vālide-i Maḳtūle" (murdered mother), and "Vālide-i Şehīde" (martyred mother).