Which composer was renowned for creating expressive Gregorian chants?

Hildegard of Bingen, a 12th-century Benedictine abbess, is renowned for her expressive Gregorian chants. She composed a significant body of sacred music characterized by its lyrical melodies and spiritual depth, often reflecting her mystical visions. Her works are notable for their originality and emotional intensity, setting her apart from her contemporaries in the realm of chant composition.