A setting of a poem written by (according to the record label site) the Greek Orthodox Saint Nectarios of Aegina , this piece was my first exposure to Greek Orthodox choral music. In St Petersburg I’ve attended Orthodox services, with their emphasis on sung liturgy. This music has something deeply urgent and fervent, different again from the Russian style.
The original poem was not intended for liturgical use:
St. Nectarios was a Bishop of the Greek Orthodox Church throughout the late 1800s, and early 1900s. Throughout the period of his episcopacy, he spent much time in prayer and contemplation, and dedicated himself to the monastic life. His spiritual lifestyle, and his particular dedication to the Virgin Mary inspired him to write a wide variety of religious poetry, much of which was published during his life, and after his repose in 1920.
One of the many poems he wrote is “Agni Parthene” or “O Virgin Pure”. According to a tradition passed down on the island of Aegina, St. Nectarios reportedly composed the text for this poem after having seen a vision of the Theotokos in a dream where she asked him to record this poem. The original script can still be viewed on his prayer table in his bedroom at this monastery.
It was later published as a poetic hymn for non-liturgical use and private edification in his publication called “Theotokarion of Odes & Hymns for the Most-Holy Theotokos and Ever-Virgin Mary” of 1905, which included many other similar poems.
The Wikipedia page goes on to clarify (albeit lacking citations):
The hymn, although not used very often in Simonopetra Monastery, nevertheless spread quickly throughout the Eastern Orthodox world and has been translated into many languages. It is most commonly performed as a concert piece in Greece, and as a recessional hymn after liturgical services in parishes throughout the United States.
The explosion in popularity has been attributed to the St. Nectarios, who has become a popular modern-day Saint.
A controversial practice has been the use of the hymn as a communion hymn and as a hymn to begin Vespers services. However, Fr. Gregory and his brethren of Simonopetra Monastery have clarified that although it has become popular, it was never meant to be used liturgically, but rather to be sung only as a non-liturgical religious song for the edification of individuals.