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 .
One of her better known works , Ordo Virtutum ( Play of the Virtues ) , is a morality play .
It is uncertain when some of Hildegard 's compositions were composed , though the morality play   is thought to have been composed as early as 1151 .
One of her better known works , Ordo Virtutum ( Play of the Virtues ) , is a morality play .