The author discusses the relation between Hildegard's musical play Ordo Virtutum and her vision on the virtues in Scivias, reading the texts of the vision and the play in the light of the dramatic events reflected in her letters during the years 1148-1152, years full of great achievement but also of a great personal loss. The correlations between the words of the play and Hildegard's letters from the beginning of the fifties invite us to conclude that it was not until after Richardis' death in 1152 that Hildegard arranged the vision into a dramatic musical morality play on the Order of the Virtues, and that it was not until then that she made the final version of the text of the vision. In giving the central roles of the play to the three first virtues of monastic life, Hildegard transforms the vision into a morality play: a play to encourage the sisters placed under her protection in the convent in their promises to live a life in humility, obedience, and chastity, resisting the temptations of the world and forming themselves and Order of Virtues.