The Crystal Cathedral

• Late Middle Ages: monastic and secular cathedrals
During the 10th and 11th centuries, the cathedral clergy became more definitely organized, and were divided into two classes. One was that of a monastic establishment of some recognized order of monks, often the Benedictines, while the other class was that of a college of clergy, bound by no vows except those of their ordination, but governed by a code of statutes or canons. Hence the name of canon. In this way arose the distinction between the monastic and secular cathedral churches. Outside of Great Britain, monastic cathedrals are known only at Monreale in Sicily and Downpatrick in Ireland.
In the case of monastic cathedral churches, the internal government was that of the religious order to which the chapter belonged, and all the members kept perpetual residence.
The alternative of this was the cathedral ruled by a secular chapter; the dignities of provost, dean, precentor, chancellor, treasurer, etc., came into being for the regulation and good order of the church and its services, while the non-residence of the canons, rather than their perpetual residence, became the rule, and led to their duties being performed by a body of "vicars", who officiated for them at the services of the church.