12th-century German mystic. Hildegard was a composer, a scientist of sorts, and a prolific writer.

She was born in 1098 into a wealthy family, and was dedicated to the church at birth. She began having visions at the age of three, but attempted to hide this gift for many years. At the age of 8, she was sent to be educated by an anchoress; when she was 38, she was elected the head of a convent.

Hildegard's major life-changing point came when she was 42 years old. She had a vision in which God told her to write down all of her visions. She had to be careful, for the Medieval church was wary of new teachings, lest they be heretical. So she obtained an imprimatur from Pope Eugenius, and finished her first book, Scivias.

Other works by Hildegard von Bingen include:
Causae et Curae, a work on natural history. In addition to other subjects, she addresses the personality types of women.
Physica, another work on natural history.
Liber divinorum operum, which records some of her mystical visions.
Ordo Virtutum, a morality play.

Hildegard also composed chants for women, in which several women chant a single melody without harmony. Her chants are growing in popularity.

Source: http://tweedledee.ucsb.edu/%7Ekris/music/Hildegard.html by Kristina Lerman.