When one begins to make any sort of systematic examination of Scottish Polyphonic Music prior to the Reformation, one is early faced with the uncomfortable realisation that, whilst a rich and abundant repertoire of works did at one time exist, pitifully few have been preserved to our own times, or are known about. The four major sources are the Scone Antiphonary, now incorporated in the National Library, the Dunkeld Music Book from the Edinburgh University Library, the three St. Andrews Music two of which are preserved in the Ducal Library at Wolfenbuttel, the third having been published in a photostat edition in 1929 by the St. Andrews University Press, and the works of the composer Robert Johnson, a native of Duns, who fled to England in the early part of the sixteenth century being delated to have been an heretic.1 By escaping he preserved not only his life but a considerable number of his compositions as well. With the exception of the St. Andrews Music Books, each of these manuscript sources provides abundant evidence that a very high standard of musical culture existed in Scotland immediately prior to the Reformation. The St. Andrews Books are of an earlier date and contain examples of the work of Perotin and his contemporaries, some of which may be Scottish in origin.