time wife Mattie "Sister Melanie" Holliday. Doc and Mattie were  never married. They were cousins, and staunch Catholics. Marrying a  blood relative was strictly forbidden by the church. Doc left  Georgia, heartbroken, when they couldnt be together, moved West and  became the outlaw we know. Mattie joined a convent and became a nun,  thus the title of "Sister Melanie".