In 1107 Anselm, archbishop of Canterbury, consecrated Urban, a priest of the church of Worcester, as bishop of Glamorgan, and Urban made a canonical profession of obedience to Anselm as primate of all Britain. Probably Urban, whose Welsh name was Gwrgan, was a member of a clerical dynasty, most likely that of Llancarfan, and had gone to Worcester, or to Worcester diocese, for his education. For a dozen years after 1107 Urban was preoccupied with shoring up his diocese in the face of the Norman conquest of Glamorgan and the impending competition from his western neighbour, Bernard, bishop of St Davids (1115–48), a formidable opponent with better connections at the English court3 According to Bernard, Urban's dispute with St Davids had already begun in the time of Bishop Wilfred (ob. 1115), Bernard's predecessor. By 1119, for the first time so far as we know, Urban was styling himself bishop of Llandaf, evidently having fixed his see close to the Norman castle of Cardiff, the caput of the new lordship of Glamorgan, where he would enjoy a mutually advantageous relationship with Robert of Gloucester, the lord of Glamorgan. Urban was probably not the first bishop to reside at Llandaf, for the mid-eleventh-century Joseph, whom Urban claimed as his predecessor but one, was described as episcopus on what appears to have been his gravestone at Llandaf; moreover Joseph's charters in the Book of Llandaf are clustered around Llandaf itself. Certainly it is difficult to imagine how Urban could have begun to attempt to foist Llandaf on his contemporaries as an ancient episcopal see if it had no history at all behind it. Llandaf need not have been a permanent see, however, for the activities of Herewald (ob. 1104), whom Urban claimed as his immediate predecessor, covered a wide area, including Gwent and Ergyng (Archenfield, southwest Herefordshire) as well as Glamorgan; Anselm referred to Herewald only as ‘a certain bishop of Wales’, not naming any see.

In 1119 Urban launched his great campaign, at first successful, to get the Pope (Calixtus II) to take the church of Llandaf under his protection and to persuade the archbishop of Canterbury to prevent the bishops of St Davids and Hereford, and various monks and Norman nobles, from despoiling it.