St. Raymond of Peñafort was a Dominican Friar, Canonist, and associate of St. Thomas Aquinas. He was born near Barcelona, Spain. He studied and taught at Barcelona for fifteen years. He then journeyed to Bologna, Italy, where he completed his studies in Canon Law and held a chair at the University from 1218-1221. At the request of the Bishop of Barcelona, he returned home and served as a Canon Lawyer.

In 1222, he entered the Dominicans at Barcelona, authoring for the order the influential manual on Canon Law for confessors, the Summa de Casibus Poenitentiae. He then served as a theologian for Cardinal Abbeville until summoned to Rome in 1229 by Pope Gregory IX.

Named chaplain and grand penitentiary, he was commanded by the pope to collect and organize the massive body of papal decretals that had accumulated during the previous years. The fruit of his work was the papal bull Rex Pacificus (1234) and the papal declaration that only Raymond's collection should be considered authoritative.

Offered the see of Tarragona, Raymond declined and chose simply to return home to Spain. Elected general of the Dominicans, he brought reforms to the constitution before retiring in 1240.

From the time he stepped down, Raymond gave himself to the cause of converting Muslims and Jews and so organized a school of Arabic and Hebrew studies. The renowned theologian St. Thomas Aquinas, at the suggestion of Raymond, wrote the Summa Contra Gentiles to assist missionaries in their efforts among non-Christians.