Constantinople in the 4th century AD, speaking on the Nativity of Jesus Christ argues that "Conceived by the Virgin, who first in body and soul was purified by the Holy Ghost, He came forth as God with that which He had assumed, One Person in two Natures, Flesh and Spirit, of which the latter defined the former." The Orthodox celebrate the Dormition of the Theotokos, rather than Assumption. The Protoevangelium of James, an extra-canonical book, has been the source of many Orthodox beliefs on Mary. The account of Mary's life presented includes her consecration as a virgin at the temple at age three. The high priest Zachariah blessed Mary and informed her that God had magnified her name among many generations. Zachariah placed Mary on the third step of the altar, whereby God gave her grace. While in the temple, Mary was miraculously fed by an angel, until she was 12 years old. At that point, an angel told Zachariah to betroth Mary to a widower in Israel, who would be indicated. This story provides the theme of many hymns for the Feast of Presentation of Mary, and icons of the feast depict the story. The Orthodox believe that Mary was instrumental in the growth of Christianity during the life of Jesus, and after his Crucifixion, and Orthodox theologian Sergei Bulgakov has written: "The Virgin Mary is the centre, invisible, but real, of the Apostolic Church." Theologians from the Orthodox tradition have made prominent contributions to the development of Marian thought and devotion. John Damascene () was one of the greatest Orthodox theologians. Among other Marian writings, he proclaimed the essential nature of Mary's heavenly Assumption or Dormition and her meditative role. More recently, Sergei Bulgakov expressed the Orthodox sentiments towards Mary as follows: Protestant Protestants in general reject the veneration and invocation of the Saints. They share the belief that Mary is the mother of Jesus and "blessed among women" (Luke 1:42) but they generally do not agree that Mary is to be venerated. She is considered to be an outstanding example of a life dedicated to God. As such, they tend not to accept certain church doctrines such as her being preserved from sin. Theologian Karl Barth wrote that "the heresy of the Catholic Church is its Mariology". Some early Protestants venerated Mary. Martin Luther wrote that: "Mary is full of grace, proclaimed to be entirely without sin.