Hymn of Kassia
Kassia, Cassia or Kassiani was a Byzantine-Greek composer, hymnographer and poet. She holds a unique place in Byzantine music as the only known woman whose music appears in the Byzantine liturgy.
Approximately fifty of her hymns are extant, most of which are stichera, though at least 26 have uncertain attribution.The authenticity issues are due to many hymns being anonymous, and others ascribed to different authors in different manuscripts. She was an abbess of a convent in the west of Constantinople.
Additionally, many epigrams and gnomic verses are attributed to her, at least 261. Kassia is notable as one of at least two women in the middle Byzantine period known to have written in their own names, the other being Anna Comnena. Like her predecessors Romanos the Melodist and Andrew of Crete, the earliest surviving manuscripts of her works are dated centuries after her lifetime.
The most famous of her compositions is the eponymous Hymn of Kassia (also known as the Troparion of Kassiani), which is chanted each year for Great and Holy Wednesday as a doxastichon occurring at the end of the aposticha of orthros and the lamp-lighting psalms of the Presanctified Liturgy.