Most of the evidence we have about magnates presenting to benefices comes from bishops' registers. This is in itself an indication of the extent of canonical authority in relation to clerical appointments. When a bishop instituted a clerk to a church, he was upholding his own spiritual authority, and it was his duty to assure the quality of local clergy by checking on the character, education and eligibility of the man presented to him. This, after all, was a moment when he might give real meaning, within his own diocese, to the drive for pastoral reform which characterised the thirteenth-century Church.

The making of canon law was one thing; putting it into effect was another. The bishop was at the sharp end of relations with lay patrons, some of whom were highly influential people, and he was also upholding the right of the patron. Canon law required that he must only admit the individual who had been presented by the true patron; and that he should do this was essential to the way in which advowson litigation was conducted in the secular courts. The assize of darrein presentment was based on who had last presented to a church and it was frequently the action used to determine advowson disputes. By exercising the right of presentation, a patron established his possession of it. At a time when being given seisin – being put in possession of property or rights – was of the utmost importance in establishing ownership, exercising the right of advowson was essential.