Saint Dominic was born in1170 at Calaruega, Spain to Felix Guzman and Bl. Joan of Aza. He studied at the University at Palencia and was appointed canon at Osma in 1199. In 1203 he accompanied Bishop Diego de Avezedo of Osma to Languedoc where Dominic preached against the Albigensians and helped reform the Cistercians. He founded an institute for women at Prouille in Albigensian territory in 1206 and attached several preaching friars to it.

When papal legate Peter of Castelnan was murdered by the Albigensians in 1208, Pope Innocent III launched a crusade. Dominic followed the army and preached to the heretics with little success.

In 1214 Simon gave him a castle at Casseneuil where Saint Dominic with six followers founded an order devoted to the conversion of the Albigensians. He failed to gain approval for his order of preachers at the fourth General Council of the Lateran in 1215 but received Pope Honorius III's approval in the following year. The Order of Preachers (The Dominicans) was founded. Saint Dominic spent the last years of this life organizing the order. He traveled all over Italy, Spain and France preaching and attracting new members. He called together the first general council of the order at Bologna in 1220 and died there the following year on August 6, 1221. He was canonized in 1234 and is the patron saint of astronomers. Feast day is Aug. 8.