All perfect praise be to Allaah, The Lord of the Worlds. I testify that there is none worthy of worship except Allaah and that Muhammad is His slave and Messenger.
We have already mentioned the wives of the Prophet in fatwa 83544, so please refer to it.
All his wives were Muslims when he married them, given that he married the mother of the believers, Khadeejah bint Khuwaylid before the revelation, and she was the first to embrace Islam.
Allaah knows best.