Reference edition:

Theodori Prisciani Euporiston libri III, cum physicorum fragmento et additamentis pseudoTheodoreis, editi a Valentino Rose ; accedunt Vindiciani Afri quae feruntur reliquiae Lipsiae 1894, pp. 484-492 (Bibliotheca Scriptorum Graecorum et Romanorum Teubneriana).

The Epistula ad Pentadium is an elementary treatise on the physiology of the humors, written in epistolary form and dedicated to Vindicianus’s grandson Pentadius.  After the preface, the text covers the following topics in order: the four humors that reside in the body; the parts of the body in which each is predominant; the qualities of the different humors; variations of humors depending on the seasons and time of day or night, the parts of the body from which each humor is expelled; their variation according to an individual’s age; the correlation between the humors and temperaments; identification of the impulses corresponding to each; and, lastly, how to care for illnesses caused by imbalance of the humors.

The work enjoyed great popularity in the medieval period, and the Venerable Bede used it in part to compose De temporum ratione 35.  Jouanna, however, has identified differences of content and terminology in the texts of Bede and Vindicianus that led him to conclude the two are independent of one another.  [M. E. Vázquez Buján; tr. C. L. Caterine].