Kassia (between 810 - bef. 865) was a Byzantine abbess, poet, composer, and hymnographer. She is one of the first medieval composers whose scores are both extant and able to be interpreted by modern scholars and musicians. 
Approximately fifty of her hymns are extant and twenty-three are included in Orthodox Church liturgical books.

Kassia (between 810 - bef. 865) was a Byzantine abbesspoetcomposer, and hymnographer. She is one of the first medieval composers whose scores are both extant and able to be interpreted by modern scholars and musicians.

Approximately fifty of her hymns are extant and twenty-three are included in Orthodox Church liturgical books.