The Sultanate of Women (Kadınlar saltanatı) was a period when wives and mothers of the Sultans of the Ottoman Empire exerted extraordinary political influence. This phenomenon took place from roughly 1533 to 1656, beginning in the reign of Suleiman the Magnificent with his marriage to Hürrem Sultan and ending with the regency of Turhan Sultan. These women were either the wives of the Sultan, referred to as haseki sultans, or the mothers of the Sultan, known as valide sultans. Many of them were of slave origin, as was expected during the sultanate since the traditional idea of marriage was considered inappropriate for the sultan, who was not expected to have any personal allegiances beyond his governmental role. During this time, haseki and valide sultans held political and social power, which allowed them to influence the daily running of the empire and undertake philanthropic works as well as to request the construction of buildings such as the large Haseki Sultan Mosque complex and the prominent Valide Sultan Mosque (also known as the Yeni Mosque (Yeni Cami) at Eminönü. This period was novel for the Ottoman Empire but not without precedent since the Seljuk rulers, the predecessors to the Ottomans, often let noble women play an active role in public policy and affairs, despite the resistance of other male officials. During the fourteenth century, the agency of women in government began to shrink. This was the age of Ottoman expansion where most sultans elected to "lead from the horse", moving around with a court of advisors, viziers, and religious leaders as the army conquered new lands. Ottoman policy from the fifteenth century onwards was to send young princes and their mothers to provincial governorships in Trabzon, Manisa and Amasya in Anatolia. This had the effect of keeping all the women with connections to the higher levels of government away from anywhere where they could hold meaningful power. The practice of fratricide—in which an ascendant sultan would execute all his brothers to secure his throne—made the wives and mothers of princes even more dependent on their men.