When we turn from the pure ‘Celtic’ diplomatic of the ‘Chad’ charters to the Book of Llandaf, we enter a more modern world. Not a page goes by without us being reminded of one or more of Urban's aspirations for his see, as we know them from his papal correspondence and elsewhere. Urban, we learn, stands at the end of an illustrious line of bishops of Llandaf whose rights suffered little infringement until the time of his predecessor, Herewald. Since the time of St Augustine these bishops had been the loyal subjects of Canterbury. – It was probably as evidence of the English connection that a list of Welsh bishops consecrated by English archbishops since Alfredian times was drawn up. – Before Augustine's arrival the bishops of Llandaf had been directly subject to the Pope, ever since their church had been founded in honour of St Peter in the time of St Germanus of Auxerre. The see's other patrons, St Dyfrig (Dubric), St Teilo (Teiliau), and St Euddogwy (Oudoce), had been the first bishops of Llandaf, and hence – naturally – Urban was entitled to all lands granted or confirmed to the saintly triad, all churches founded by them, and even many of the churches merely dedicated to them. Since the twelfth-century cults of Dyfrig and Teilo were centred in south-west Herefordshire and south-west Wales respectively, the area of Llandaf's interest was vast, and some of Urban's territorial claims even lay outside the diocese that he claimed. That diocese stretched from the Wye to the Tywi and extended through Gower into Carmarthenshire to the west and through Breconshire and Herefordshire to the north and east. Urban maintained that its bounds followed the (alleged) extent of a primitive Welsh kingdom of Morgannwg, evidently not sharing the opinion of most modern scholars that Morgannwg takes its name from a tenth-century Morgan, king of Glywysing. LL (pp. 69 and 133) even claims that until the time of St Euddogwy the diocese extended beyond the Tywi through Dyfed to insula Teithi. This justified claims to properties in the west granted to Euddogwy's alleged predecessor, St Teilo.

Urban seems to have convinced the knowledgeable among his contemporaries no more than he convinces us, and his successors inherited a small diocese similar to the diocese of Llandaf as it existed until 1920.