What was Hildegard von bingen, a gifted compser during the midddle ages, best known for

There are more surviving chants by Hildegard than by any other composer from the entire Middle Ages, and she is one of the few known composers to have written both the music and the words. One of her works, the Ordo Virtutum, is an early example of liturgical drama and arguably the oldest surviving morality play.

the answer of "what has three legs but never walks" is a yard stick. this answer can be found at