The Sultanate of Women (Turkish: Kadınlar Saltanatı) was the nearly 130-year period during the 16th and 17th centuries when the women of the Imperial Harem of the Ottoman Empire exerted extraordinary political influence over state matters and over the (male) Ottoman sultan, starting from the reign of Suleiman the Magnificent. Many of the Sultans during this time were minors and it was their mothers, the Valide Sultans, or their wives, the Haseki Sultans, who effectively ruled the Empire. Most of these women were of slave origin, which was often the case in general for consorts of Ottoman sultans.
The period commonly known as the Sultanate of Women was novel for the Ottoman Empire, but not without precedent. The Seljuks, predecessors to the Ottoman Empire, often had women of nobility playing an active role in public policy and affairs, despite the concern of other male officials.
However, during the fourteenth century, the agency of women in government began to shrink considerably. This was the age of Ottoman expansion, and as such, most Sultans elected to "lead from the horse", moving with a court of advisors, viziers, and religious leaders as the army conquered new lands. In addition, Ottoman policy from the fifteenth century onward was to send young princes and their mothers to provincial governorships in Anatolia. In effect, this kept all of the women with connection to the higher levels of government far away from any place where they could hold meaningful power. What's more, the practice of fratricide—in which an ascendant sultan would execute all his brothers to secure his throne—made the mothers and wives of princes even more dependent on their men.
Fortunes began to change, however, with the beginning of the 16th century, and the concurrence of two significant events: the end of Ottoman expansion, and the merging of the imperial harem into the palace proper. During the reign of Suleiman the Magnificent, it became clear that the empire had reached its outer limits, with borders stretching thousands of miles in nearly every direction, the sultan simply could no longer afford to go on extended military campaigns, especially after the failure of the Siege of Vienna. The vastness of the empire also made the Beylerbeylik system increasingly impractical, and as such the princes began to move back to the capital. However, with their primary military and economic strength neutralized, there was no longer a need for the practice of fratricide.