 Light was associated with Mary and the Incarnation from the 9th century . Millard Meiss notes that , from the 12th century a common way to convey the conception was to compare light passing through glass to the passage of the Holy Spirit through the body of the Virgin . St. Bernard likened it to sunshine explaining in this passage : " Just as the brilliance of the sun fills and penetrates a glass window without damaging it , and pierces its solid form with imperceptible subtlety , neither hurting when entering nor destroying when emerging ; thus the word of God , the splendor of the Father , entered the virgin chamber and then came forth from the closed womb . " 
