Valide Sultan was the title of the mother of the reigning sultan. The mothers who died before their sons' accession to throne, never assumed the title of Valide Sultan like Hürrem, Muazzez, Mihrişah,[1][2] and Şermi.[3] On the other hand, step mothers who were not the biological mothers but raised the princes whose mothers had died assumed the title of Valide Sultan like Perestu. So there were Valide Sultans who were not the mothers, and there were mothers who were not the Valide Sultans.