Question: Who gave a reason for the purging of evil for the Blessed Virgin and her first child ?
Sentence: After this period, the "purification" of the perfect natures of Jesus and Mary would not only mean moments of grace and glory at the Incarnation and Baptism and other public Byzantine liturgical feasts, but purification was eventually associated with the feast of Mary's very conception (along with her Presentation in the Temple as a toddler) by Orthodox authors of the 2nd millennium (e.g., St. Nicholas Cabasilas and Joseph Bryennius).
Answer in sentence: no