Without question, one of the most familiar texts to students of medieval music is the often-cited passage in the treatise of Anonymous IV that offers an account of the historical development of the Notre-Dame tradition. I introduce my own discussion of the ‘making’ of the Parisian liber organi with a brief consideration of this famous text.The Latin is, with minor adjustments, that of F. Reckow, Der Musiktraktat des Anonymus 4, 2 vols. (Beihefte zum Archiv für Musikwissenschaft, 4-5; Wiesbaden, 1967), i, pp. 45-6. The translation is my own, but it has benefited from suggestions by Leofranc Holford-Strevens (most important among them, the readings of ‘optimus organista’ and ‘optimus discantor’ as ‘an excellent organista’ and ‘an excellent discantor’).