 It is uncertain when some of Hildegard's compositions were composed, though the "Ordo Virtutum" is thought to have been composed as early as 1151.It is an independent Latin morality play with music (82 songs); it does not supplement or pay homage to the Mass or the Office of a certain feast.The most significant part of this entire composition is, however, that the "Ordo virtutum" is the earliest known surviving musical drama that is not attached to a liturgy.