Christianity spread in Scotland from the sixth century, with evangelisation by Irish-Scots missionaries and, to a lesser extent, those from Rome and England. The church in Scotland attained clear independence from England after the Papal Bull of Celestine III (, 1192), by which all Scottish bishoprics except Galloway became formally independent of York and Canterbury. The whole , with individual Scottish bishoprics (except Whithorn/Galloway), became the "special daughter of the see of Rome". It was run by special councils made up of all the Scottish bishops, with the bishop of St Andrews emerging as the most important figure. The administration of parishes was often given over to local monastic institutions in a process known as appropriation. By the time of the Reformation in the mid-sixteenth century 80 per cent of Scottish parishes were appropriated, leaving few resources for the parish clergy.