Source: The English translation of The Liturgy of the Hours (Four Volumes)
Saint Dominic was born in 1170 at Calaruega, Spain, was educated in the schools of 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 (heresy) and helped reform the Cistercians.
He founded an institute at Prouille in Albigensian territory in 1206 and attached several preaching friars to it. In 1208 a papal legate was murdered by Albigensians and Pope Innocent III launched a crusade against them.
Dominic followed this crusade and preached to the heretics. In 1214 Dominic with six followers founded an order devoted to the conversion of the Albigensians and so the Order of Preachers (the Dominicans) was founded. This organization has as its motto “to praise, to bless, to preach” (Latin: Laudare, benedicere, praedicare), taken from the Preface of the Blessed Virgin Mary in the Roman Missal.
Dominic spent his last years of this life organizing the order, preaching and attracting new members and establishing new houses. He subjected himself and his companions to the monastic rules of prayer and penance.
Death came at the age of fifty-one and found him exhausted with the austerities and labors of his eventful career. He refused to rest in a bed and made the monks lay him on some sacking stretched upon the ground. The brief time that remained to him was spent in exhorting his followers to have charity, to guard their humility, and to make their treasure out of poverty. He died at noon on 6 August 1221.
He was canonized in 1234 and is the patron saint of astronomers.
St. Dominic, ora pro nobis!