Musnad Ahmed: Hadith 3237

Maimoonah the wife of the Prophet (ﷺ), the maternal aunt of Ibn 'Abbas (رضي الله عنه), died. He ['Ata'] said: I went with him to Sarif. He praised and glorified Allah, then he said: She is the Mother of the Believers, do not shake her; be gentle with her, for the Prophet of Allah (ﷺ) had nine wives, and he used to give a share of his time to eight and did not give a share of his time to the ninth - meaning Safiyyah bint Huyay. 'Ata' said: She was the last of them to die; she died in Madinah.