Kassia or Kassiani was born into a wealthy Constantinople family between about 805- 810AD.
She rejected the proposal of Theophilos, who was destined to become emperor at the time.
Instead, Kassia became a nun, founding a convent in the western part of Constantinople, where she was the first abbess.
She was a composer of religious poetry and also composed music. Unlike some of the other early musical ladies on here, many of Kassia’s works are still extant, and still used in Byzantine liturgy today.
The emperor Theophilos was an iconoclast, meaning he didn’t believe in the worship of icons, and Kassia suffered for her beliefs under his reign. When his son Michael III came to power, the iconoclastic period came to an end.
Kassia eventually settled on the Greek island of Kasos and her tomb and reliquary can be found in a church in the city of Panaghia.
Some of her works can be heard here: https://www.youtube.com/watch?v=ioWWIiG_sHc
I don’t understand the language at all but the music is lovely, and the harmonies are amazing. It’s the kind of music that makes you feel like you’re flying.
Source: (which also includes links to more of her compositions) https://en.wikipedia.org/wiki/Kassiani
Next up on the awesome ladies project is Chinese astronomer, Wang Zhenyi.