Basil was a notable figure during the period when the Eastern Church was convulsed by the Eutychian controversy, and was necessarily obliged to take sides in all the attendant disputes.
"[6]: 72 In the well-known homily On the Annunciation now generally recognised as authentic[6]: 71-72 (for discussion of which, see 'Writings' below), Basil bears witness to a highly developed Marian theology.
Written in the highly-charged theological climate after the Council of Ephesus, the homiletic hymn is of a devotional nature, bearing witness to the blossoming of Mariologial thought.
O'Carroll notes that "he cannot praise the Theotokos fittingly", declaring that she is the temple truly worthy of God, and "shines above all the martyrs as the sun outshines the stars",[6]: 72 language consistent with earlier contemporaries like Proclus and Cyril.
Likewise, Basil makes use of salutatory invocations beginning with Χαῖρε ("Hail")[7] which would become a mainstay of Marian devotion in subsequent centuries.
O'Carroll additionally observes that Basil "marks an advance" over previous theologians in his teachings on Marian intercession, wherein the bishop sets forth a clear understanding of the Virgin's mediatorial capacity, and strongly links it with her divine motherhood.
At the same time, his direct invocation of the Theotokos with royal appelations and a plethora of praises of her exalted status suggests a developing understanding of such a capacity on the Virgin's part.
Limberis observes that Basil's hymnic oration "reflect[s] the growth of the cult of the Theotokos, sanctioned by the bishops, incorporated into the liturgical cycle of the year.