Catalan Dominican friar who compiled the Decretals (decretal) of Gregory IX, a body of medieval legislation that remained part of church law until the Code of Canon Law was promulgated in 1917.

He studied canon law at Bologna and taught there from 1218 to 1221. Among his works of this period were unpublished annotations of the Decretum (Gratian's Decretum) of Gratian (flourished c. 1140; the father of the science of canon law) and an uncompleted treatise on canon law, Summa juris canonici.

After his return to Barcelona in 1222, he joined the Dominican Order and wrote a manual of canon law for confessors, Summa de casibus poenitentiae (“Concerning the Cases of Penance”), one of the most widely used books of its kind during the later Middle Ages.

In 1230 Pope Gregory IX called Raymond to Rome to serve as a papal chaplain to examine cases of conscience. Gregory also commissioned him to codify the papal statutes and rulings on points of canon law that had been issued since the appearance of Gratian's Decretum. Raymond's compilation of Gregory's Decretals was formally promulgated in 1234. The following year he revised and reissued his Summa de casibus, with an added part on the law of matrimony.

He returned to Spain (1236) and in 1238 was elected master general of the Dominican Order. Although he resigned after only two years, he revised the constitutions of the order. The remainder of his life was devoted to various papal commissions and to missionary interests. Later he organized schools of Arabic and Hebrew studies for missionaries in Tunis and in Murcia (c. 1255), an independent Muslim kingdom in Spain. It was at his request that St. Thomas Aquinas wrote the Summa contra gentiles, a theological exposition against the heathens.