Theodore the Studite
Kassiani wrote many hymns which are still used in the Byzantine liturgy to this day. Kassiani became known to the great Theodore the Studite, while she was still a young girl, and he was impressed by her learning and literary style. She not only wrote spiritual poetry, but composed music to accompany it. She is regarded as an "exceptional and rare phenomenon" among composers of her day At least twenty-three genuine hymns are ascribed to her.