Juana de Aza is the name gradually developed in hagiographical tradition for the mother of Saint Dominic and Bl.

In the final form of this tradition, she is said to have been born in about 1135 in Haza and to have died at Caleruega (Dominic's birthplace) on 4 August 1205.

[3] Nearly a century after Dominic's birth, a local author asserts that Dominic's father was vir venerabilis et dives in populo suo ("an honoured and wealthy man in his village");[4] later hagiographers, elaborating on this, gradually developed identities for his father, said to be a member of the local noble family Guzmán and for his mother, who was eventually attached to the neighbouring noble Aza family.

[6] According to Dominican tradition, his mother later saw the moon on his forehead, yet at his baptism, his godmother perceived it as a star.

The boy was named probably after Saint Dominic of Silos whose nearby shrine was a favorite of his mother.