In 1895 (Acad., Sept. 21, p. 227), Professor Liddell announced that he had in preparation conclusive evidence to show that Chaucer in his translation of Boethius had used (in addition to the Latin text) the French prose translation ascribed to Jean de Meung. In 1897, again (Nation, Feb. 18, pp. 124 f.), Professor Liddell declared his belief that Chaucer, as well as the French translator from whom he borrows, in making their Boethius translations, worked with the Latin commentary wrongly ascribed to Thomas Aquinas. And last year, having occasion to examine the Latin commentary on Boethius by Nicholas Trivet, I found there ample evidence, as I think, to give Trivet's commentary an important place among the sources of Chaucer's Boethius. Two commentaries in addition to the Latin text and a French translation make an equipment which seems extraordinarily elaborate for the circumstances. However, an examination of the two commentaries discovers the fact that Trivet's commentary includes the glosses of the other, in most of the cases in which Chaucer is concerned; and it is the object of this note to furnish evidence which points to Trivet's commentary as the single source of this material in Chaucer's Boethius.