Before the twelfth century most Scottish churches had collegiate bodies of clergy who served over a wide area, often tied together by devotion to a particular missionary saint. From this period local lay landholders, perhaps following the example of David I, began to adopt the continental practice of building churches on their land for the local population and endowing them with land and a priest, beginning in the south, spreading to the north-east and then the west, being almost universal by the first survey of the Scottish Church for papal taxation in 1274. The administration of these parishes was often given over to local monastic institutions in a process known as appropriation. Scotland had little clear diocesan structure before the Norman period. There were bishoprics based on various ancient churches, but some are very obscure in the records and there appear to be long vacancies. From around 1070, in the reign of Malcolm III, there was a "Bishop of Alba" resident at St. Andrews, but it is not clear what authority he had over the other bishops. After the Norman Conquest of England, the Archbishops of both Canterbury and York each claimed superiority over the Scottish church. The church in Scotland attained independent status after the Papal Bull of Celestine III ("Cum universi", 1192) by which all Scottish bishoprics except Galloway were formally independent of York and Canterbury. However, unlike Ireland, which had been granted four Archbishoprics in the same century, Scotland received no Archbishop and the whole "Ecclesia Scoticana", with individual Scottish bishoprics (except Whithorn/Galloway), became the "special daughter of the see of Rome". It was in practice run by special councils made up of all its bishops, with the bishop of St Andrews emerging as the most important player.