Is the title "Umm al-Mu'minin" (Mother of the Believers) applied to Maria al-Qibtiyya, who bore the Prophet, peace and blessings be upon him, his son Ibrahim, and who was his (right-hand possession)?

The Prophet Muhammad, peace be upon him, did not marry Mariya al-Qibtiyya. Rather, she was a slave woman given to him as a gift by al-Muqawqis, the ruler of Egypt. She embraced Islam, may Allah be pleased with her, and bore the Prophet, peace be upon him, his son Ibrahim. Mariya al-Qibtiyya is not considered one of the Mothers of the Believers, because the Mothers of the Believers are the wives of the Prophet, peace be upon him, whereas Mariya was one of his four slave women. Mariya died during the caliphate of Umar ibn al-Khattab in the year sixteen [Hijri]. Umar prayed over her and she was buried in al-Baqi'.