Diaz was born in the city of Oazaca on the September 15, 1830. His father was Jose Faustino Diaz and his mother Petrona Mori. Though they came from Spain, his father was part of what was called the Creole race, which is to say, with some mix of Native American blood. His paternal grandparents were Manuel Diaz and Marcela Bohorquez, both from Oaxaca, and his maternal grandparents were Mariano Mori and Tecla Cortez from Yodocono.
Nací en la ciudad de Oaxaca el 15 de septiembre de 1830. Mi padre fue José Faustino Díaz y mi madre, su esposa, Petrona Mori. Aunque de origen español, mi padre era de los que llamamos raza criolla, es decir, con alguna mezcla de sangre india. Mis abuelos paternos fueron Manuel Díaz y Marcela Bohórquez, ambos de Oaxaca; y mis abuelos maternos Mariano Mori y Tecla Cortés, de Yodocono.