Guarino Guarini of Verona (1374-1460) dedicated much of his philological work to the study of Plutarch, translating all in all thirteen of his Parallel Lives. His Latin version of the Life of Dion (1414) was dedicated to Francesco Barbaro, the Venetian noble who was one of Guarino's favourite pupils and himself a translator of Plutarch. We possess the presentation copy of Guarino's translation, the autograph MS Bywater 38 of the Bodleian Library, which also contains a series of interesting annotations by Guarino. The Life of Dion relates how the Sicilian statesman, brother- and son-in-law of Dionysius I of Syracuse, tried to realize the ideal of the philosopher-king under the guidance of Plato; Guarino's annotations are to a large extent concerned with the philosophical and political aspects of the life, undoubtedly reflecting the interests of the dedicatee of the translation, Barbaro. They were copied in several later manuscripts and offer fascinating insights into the way fifteenth-century readers addressed the Plutarchan life. Guarino's Dion is transmitted in manuscripts containing larger or smaller selections of the humanist translations of Plutarch's Lives. It is extant in 40 manuscripts, the latest, now probably lost, dating from a. 1511. From 1470 and onwards the translation was included in the numerous printed edition of the entire corpus of the Latin lives, but no modern edition of the translation exists prior to the present one.