At the time that Cyril administered the church

At the time that Cyril administered the church of Jerusalem after Maximus, the sign of the cross appeared in the heavens. It shone brilliantly, not with divergent rays like a comet, but with the concentration of a great deal of light, apparently dense and yet transparent. Its length was about fifteen stadia from Calvary to the Mount of Olives, and its breadth was in proportion to its length. So extraordinary a phenomenon excited universal terror. Men, women, and children left their houses, the market-place, or their respective employments, and ran to the church, where they sang hymns to Christ together, and voluntarily confessed their belief in God. The intelligence disturbed in no little measure our entire dominions, and this happened rapidly; for, as the custom was, there were travelers from every part of the world, so to speak, who were dwelling at Jerusalem for prayer, or to visit its places of interest, these were spectators of the sign, and divulged the facts to their friends at home. The emperor was made acquainted with the occurrence, partly by numerous reports concerning it which were then current, and partly by a letter from Cyril the bishop. It was said that this prodigy was a fulfillment of an ancient prophecy contained in the Holy Scriptures. It was the means of the conversion of many pagans and Jews to Christianity.

Hermias Sozomen. Historia eclesiástica, IV, 5.