his Baptism by John he tends not to be shown with a halo, it being a matter of debate whether his Logos was innate from conception (the Orthodox view), or acquired at Baptism (the Adoptionist view). At this period he is also shown as a child or youth in Baptisms, though this may be a hieratic rather than an age-related representation. A cruciform halo, that is to say a halo with a cross within, or extending beyond, the circle is used to represent the persons of the Holy Trinity, especially Jesus, and especially in medieval art. In Byzantine and Orthodox images, inside each of the bars of the cross in Christ's halo is one of the Greek letters Ο Ω Ν, making up —"ho ōn", literally, "the Existing One"—indicating the divinity of Jesus. At least in later Orthodox images, each bar of this cross is composed of three lines, symbolising the dogmas of the Trinity, the oneness of God and the two natures of Christ. In mosaics in Santa Maria Maggiore (432–40) the juvenile Christ has a four-armed cross either on top of his head in the radius of the nimbus, or placed above the radius, but this is unusual. In the same mosaics the accompanying angels have haloes (as, in a continuation of the Imperial tradition, does King Herod), but not Mary and Joseph. Occasionally other figures have crossed haloes, such as the seven doves representing the Seven gifts of the Holy Spirit in the 11th century Codex Vyssegradensis Tree of Jesse (where Jesse and Isaiah also have plain haloes, as do the Ancestors of Christ in other miniatures). Later, triangular haloes are sometimes given to God the Father to represent the Trinity. When he is represented by a hand emerging from a cloud, this may be given a halo. Plain round haloes are typically used to signify saints, the Virgin Mary, Old Testament prophets, angels, symbols of the Four Evangelists, and some other figures. Byzantine emperors and empresses were often shown with them in compositions including saints or Christ, however the haloes were outlined only. This was copied by Ottonian and later Russian rulers. Old Testament figures become less likely to have haloes in the West as the Middle Ages go on. Beatified figures, not yet canonised as saints, are sometimes shown in medieval Italian art with linear rays radiating out from the head, but no circular edge