His legendary Vita dates from the 12th century and exists in 20 different documents. His legend states that in 344, he brought the relics of the Three Magi from Constantinople to Milan, with two small cows which transported a large sarcophagus of marble. (Photo: Empty shrine in St. Eustorgio, ca. 300 AD)
The relics of the Magi were taken from Milan by Holy Roman Emperor Fredrick Barbarossa and given to the Archbishop of Cologne, Rainald of Dassel, in 1164. A Shrine of the Three Kings at Cologne Cathedral still exists.
The Vita Beati Eustorgii Confessoris reports around the year 1200:
"... The holy Helena, mother of the emperor Constantine, was one with all virtues affected and a very much pious woman regarding the Christian religion. Therefore she proved uncommon eagerness in collecting relics of the holy ones. She traveled in own person through those widen countries of the Roman realm to the Orient and to the Western World. There she built over the bodies of the martyrs, who were killed by cruelty of tyrants because their Christian names, substantial memorials. Apart from the many fameful proofs of her piety to God she also accumulated the bodies of the Three Magi together, who were buried in different places, and Helena brought the bodies towards Constantinople. In this city they remained in large honours until the times of the emperor Manuel. At that time Eustorgius lived, Greek birth, a very informed man, nobly and piously, of pleasing exterior, eloquently, for the service to God quite been suitable and in this service turned, a guard of the faith, and also chaste, and a native from Constantinople, before the times of bishop Saint Ambrose of Milan. He came as an ambassador of the emperor Manuel to Milan, and the people of Milan selected him to bishop. Therefore Eustorgius returned to Constantinople, said thanks to the emperor and spoke: My father and emperor Manuel, I thanks you that you have appreciated the honour towards me up to now and that you have sent me into the holy city Milan, your metropolis. You should know that I have achieved everything, faithfully and after your will, the deliveries are always secured for you, but I am however the chosen one of the city, because you, in honour of God and to praise his charitableness. I unworthy one was urgent asked to return and to announce, what in the view on our God and on you your you faithfully resulted people have done at me and like the people delegated these envoys with me to you. Intend mine and instruct, what I am to do. The emperor answered: Become bishop, worthy man. Eustorgius answers: I thank God and you; but allow, dearest gentleman, that I can carry forward and can take away to the holy city of Milan anything of the sanctuaries, which me liked, if God's benignity permits it, in order to honour the church with holy relics, and as a gratification for your tributary people. The emperor answers: Select, receive, carry forward, which you would like. Be as if you are, or, is it possible, become still better. Greet my people and announce that from now on the whole delivery is issued. Thus Eustorgius went pleased, and he manufactured a marmorean coffin with large effort, and put into it the bodies of the Three Kings, who had brought Christus their gifts - gold, frankincense and myrrh. With trouble under many nights in which he was awake, and through God's assistance and amicability he transported it towards Milan into the city. The sarcophagus became buried outside of the city-wall closely beside the city in a church, which later was sanctified to honor holy Eustorgius. Also there is a famous and very holy source, where the neophytes had received the holy baptism, all Christians pious veneration with dignity. ..."