Hildegard was a remarkable woman that lived in the 12th century. She was of German decent and became a nun at the age of 15. She was a poet, a physician, as well as a moralist.
She was constantly rebuking princes, bishops and popes in a fearless manner when she did not approve of their actions. She was able to foretell the future and she wrote her visions down. An archbishop later declared that her visions had come from God. In total, she had 26 visions. She wrote more than 300 letters to kings and popes with prophecies and warnings.
Later, Pope Eugenius III read her writings and told her to write whatever the Holy Spirit told her to do. With the blessing of her pope, she built a large monastery and had such things as running water for her and the other nuns.
St. Hildegard has never officially been canonized, though she is still listed as a saint by Roman Martyrology. She is the patron saint of ecology as well as musicians and writers.