The dean's right to appoint and discipline the prebends was recognised. The bishop was to intervene only in the last resort, if the dean was not carrying out his functions. For his part, the dean recognised the bishop's right to be received with honour at St Peter's and to administer the sacraments there. However the whole issue blew up again in 1260, when Erdington repelled an attempt by Bishop Roger de Meyland to hold a canonical visitation by getting a royal prohibition on 8 November "against any person attempting anything against the privileges of Giles de Erdinton, king's clerk, dean of Wolverhampton, or of the king's chapel of Wolverhampton, or of the canons or servitors there." The prohibition cited a Papal rescript, issued at Lyon in 1245, that guaranteed the independence of royal chapels, which it characterised as "ecclesiae Romanae immediate subjecta", directly subordinate to the Roman Church. They were therefore immune even from excommunication and interdict pronounced at a lower level, which disarmed the local bishop in his dealings with them. Erdington was equally vigorous in promoting the economic interests of the college. Sometimes this meant taking a firm line over local issues: in 1230 he literally raised a stink by taking legal action against a chaplain at Tettenhall over marshland at Codsall that was creating a health hazard. Property agreements were carefully recorded, often by the device of a fine of lands, a conveyance registered by a fictional lawsuit. On 18 November 1236, for example, he was notionally sued for land at Kinvaston by Athelard: the two sides came to an agreement that Athelard's family would rent 1½ virgates from the dean and his successors for ½ mark annually. To make clear the college's territorial sway, he had the boundaries walked ceremonially. In 1248, for example, the king ordered the sheriff to organise a perambulation with twelve knights near Codsall where the College's lands bordered the Oaken estate of Croxden Abbey. Sometimes it was necessary to pursue offenders. In June 1253 the Dean and Chapter prosecute 39 local men who had entered the College's lands as an armed band, destroying fences and crops. None turned up in court and their sureties proved worthless, so the sheriff was ordered to take appropriate action. Erdington was concerned that the church benefit from the town's booming trade, which was based mainly on wool. In 1258 Erdington secured for the deanery the lucrative right to hold a "weekly market on Wednesaday at Wolverhampton, co. Stafford, and of a yearly fair there on the vigil and Feast of Saints Peter and Paul and the six days following," both of which took place thereafter at the foot of the church steps.