St. Augustine speaks of his work On Continence in Ep. 231, Ad Darium Comitem. [See vol. 1. of this edition, p. 584.— P.S.] Possidius, Ind. c. 10, mentions it, and it is cited in the Collectanea of Bede or Florus, and by Eugypius. Erasmus is therefore wrong in ascribing it to Hugo on the ground of the style, which is not unlike that of the earlier discourses. It is evidently a discourse, and probably for that reason unnoticed in the Retractations. The Manichæan heresy is impugned after the manner of his early works.— (Abridged from Benedictine ed. vol. vi.)
Source: On Continence (New Advent)