Dominic was born in 1170 at Calaruega, Burgos, Old Castile of wealthy Spanish nobility, the son of Blessed Joan of Aza. When she was pregnant, his mother had a vision that her unborn child was a dog who would set the world on fire with a torch it carried in its mouth; a dog with a torch in its mouth became a symbol for the order which he founded, the Dominicans.

At Dominic's baptism, Blessed Joan saw a star shining from his chest, which became another of his symbols in art, and led to his patronage of astronomy.

He studied philosophy and theology at the University of Palencia , was ordained and become canon of the cathedral of Osma. As an Augustinian, he worked for clerical reform. He carried out a lifelong apostolate among heretics especially in France and founded the Order of Friars Preachers (Dominicans) in 1215, a group who live a simple, austere life, and an order of nuns dedicated to the care of young girls.

At one point Dominic became discouraged at the progress of his mission; no matter how much he worked, the heresies remained. But he received a vision from Our Lady who showed him a wreath of roses, representing the rosary. She told him to say the rosary daily, teach it to all who would listen, and eventually the true faith would win out. Dominic is often credited with the invention of the rosary; it actually pre-dates him, but he certainly spread devotion to it, and used it to strengthen his own spiritual life.

He died Aug. 4, 1221 at Bologna and was canonized on July 13, 1234 by Pope Gregory IX at Rieti, Italy.