Churches known as "collegiate" were ecclesiastical corporations constituted in a way that reflected the foundations of the cathedrals with a chapter of secular canons. With two exceptions, Dunbar and Bothwell, they were all founded later than the year 1400, after which date they become numerous. The years between 1440 and 1460 were particularly prolific in foundations of this kind, some thirteen or fourteen collegiate churches being erected in various parts of the country during those twenty years. Similar foundation were made from time to time till 1545, when Biggar, in Lanark, closed the series. In all, from 1342 to 1545, nearly forty collegiate churches were founded, of which two-thirds belong to the fifteenth century.
It became a favourite expression of devotion on the part of great nobles, large land-owners, and sometimes kings or members of the royal family, to endow a church for the maintenance of divine service on a scale of completeness and ceremonial dignity that would have been impossible in an ordinary parish church. Lands, or the free revenues of parish churches which were subject to their patronage would be conveyed by the founders for the support of the new foundation. The clergy would have, as in the case of canons of cathedrals, each his separate prebend. The then prevailing belief in the benefits of masses said for the departed had for long stimulated the foundation of chantry chapels in the cathedrals and greater parish churches. The same sentiments now moved men to the foundation of the collegiate churches, where the souls of the founders, whose bodies were often buried in the church they had founded, and the members of their families were secured a large amount of such benefits as were believed to be obtained by frequent prayers and masses.
The head of the collegium was ordinarily styled the provost (prepositus) and these foundations are commonly referred to in ecclesiastical documents as prepositurae. Occasionally, as in the case of Dunbar, Restalrig, and the Chapels Royal, the head was known as the dean, reflecting the practice in cathedral chapters. Under the provost or dean were a number of prebendaries known either as canons or chaplains. Their number varied with the wealth of the foundation. At St. Giles in Edinburgh there were 16, including the sacrist and "minister of the choir"; at Lincluden, 12; at Tain and at Crail, 11; at Crichton, 9; at Trinity College, Edinburgh, 8; at Yester, 7. At Roslin, Seton, Carnwath, Kilmun, and Dumbarton, there were 6. At Costorphine there were 5; at Maybole and at Semple there were 3. Sometimes, just as in the case of cathedrals, a new prebend would be granted by some benefactor, and the number of chaplains or canons thus increased.
In a large number of cases two or more boy-choristers were to be maintained on the foundation; and in a few instances provision was also made for the support of a number of almsmen.
In some cases the patronage of the whole or of some of the prebends was retained in the hands of the founder's family. This enabled the family to appoint some of their own kin to places of dignity and emolument. This was so in the case of Dunbar where for many years the patronage lay in the hands of the earls of March.
There was no uniform system for the constitution of collegiate churches and the foundation charters of each require separate consideration. In most, if not all of the collegiate churches, provisions are found for continuous residence of the prebendaries, and for the cultivation of what was then reckoned to be a high quality of sacred music. Not only were the clergy to be versed in the Gregorian or plainsong, but in some cases they were also to be learned "in discant and pricket-sang", the harmony and counterpoint of the day. As was the case with a number of cathedrals there were sometimes "sang schules" attached to the collegiate churches.
In this way, the tradition of daily services was maintained not only in Scotland's cathedrals but in the smaller but often sumptuously provided collegiate churches. The prebendaries were often provided with a house or, at least, lodgings in the vicinity of the college in addition to the revenues they obtained from their prebends. They often offered education to the founder's family and others who might be lucky enough to be able to take advantage of it and they contributed greatly to the advancement of the art of church music. One cannot fully appreciate the medieval church in Scotland without taking full account of the prepositurae.