As part of their mission to preach faith and morals, the medieval Dominicans often served as allies of parochial clergy and the episcopate. Scholars such as M. Michèle Mulchahey have shown that on the Continent, the Order of Preachers often helped to educate parish priests. We have evidence that thirteenth- and fourteenth-century Dominicans were allowing parochial clergy to attend their schools in England as well. Much of this evidence is codicological. Two English codices of William Peraldus's sermons provide evidence of a provenance relating to a parish church: London Gray's Inn 20, a collection of his sermons on the Gospels, was owned by a parish priest, and Cambridge Peterhouse 211, a manuscript of his sermons on the Epistles, contains an act issued by the rector of a parish church. Another manuscript of Peraldus's sermons contains synodal statutes. As the Order of Preachers was outside of the diocesan chain of command, these statutes point to the use of these sermons by those who were subject to the episcopate.
Since the Dominicans were normally forbidden from sharing their model sermon literature with secular clergy, these codices suggest a program on the part of the English province of the Order of Preachers to make sure that diocesan clergy could attend Dominican schools in order to gain the skills necessary to preach the basic doctrines and morals of the Christian faith to England's laity.