The International character of Christine de Pisan's writings has long ago been investigated where it concerns her familiarity with the works of her compatriots Dante and Boccaccio or her relations with the English court during the early years of the fifteenth century. Considerably less well known is the Portuguese translation of her Livre des trois vertus, which is to be found in MS. 11,515 of the National Library in Madrid. This translation was, furthermore, published in Lisbon in 1518. Although two copies of the edition still exist and are listed in Portuguese bibliographies, the only mention of such a translation among studies devoted to Christine de Pisan is a passing refererence in Mathilde Laigle's Livre des trois vertus: son milieu historique et litteraire (Paris, 1912). Here a footnote promises further information in a projected edition of the Trois vertus which has never appeared. Several years later the Portuguese translation was referred to by Aubrey Bell in his Portuguese Literature, but with several errors of detail. As the existence of the manuscript and the two printed copies cannot fail to arouse the curiosity of any student of Christine de Pisan's writings or, indeed, of the intellectual currents of the late Middle Ages, it would seem worth while to attempt a plausible explanation of the circumstances which brought the Portuguese version into being.