Julius was a native of Rome and was chosen as successor of Pope Mark after the Roman seat had been vacant for four months.
Arianism
Julius is chiefly known by the part he took in the Arian controversy. After the followers of Eusebius of Nicomedia, who had become the patriarch of Constantinople, renewed their deposition of Athanasius of Alexandria at a synod held in Antioch in 341, they resolved to send delegates to Constans, emperor of the West, and also to Julius, setting forth the grounds on which they had proceeded. Julius, after expressing an opinion favourable to Athanasius, adroitly invited both parties to lay the case before a synod to be presided over by himself. This proposal, however, the Arian Eastern bishops declined to accept. On this second banishment from Alexandria, Athanasius came to Rome, and was recognised as a regularbishop by the synod presided over by Julius in 342. Julius sent a letter to the Eastern bishops that is an early instance of the claims of primacy for the bishop of Rome. Even if Athanasius and his companions were somewhat to blame, the letter runs, the Alexandrian Church should first have written to the pope. "Can you be ignorant," writes Julius, "that this is the custom, that we should be written to first, so that from here what is just may be defined". It was through the influence of Julius that, at a later date, the council of Sardica in Illyria was held, which was attended only by seventy-six Eastern bishops, who speedily withdrew to Philippopolis and deposed Julius at the council of Philippopolis, along with Athanasius and others. The three hundred Western bishops who remained, confirmed the previous decisions of the Roman synod and issued a number of decrees regarding church discipline. The first canon forbade the transfer of bishops from one see to another, for if frequently made, it was seen to encourage covetousness and ambition. By its 3rd, 4th, and 5th decrees relating to the rights of revision claimed by Julius, the council of Sardica perceptibly helped forward the claims of the bishop of Rome. Julius built several basilicas and churches.
Christmas
Around 350, Julius I declared December 25 as the official date of the birth of Jesus, around the same time as the festival of Saturnalia; the actual date of Jesus's birth is unknown. Some have speculated that part of the reason why he chose this date may have been because he was trying to create a Christian alternative to Saturnalia. Another reason for the decision may have been because, in 274 AD, the Roman emperorAurelian had declared 25 December the birthdate of Sol Invictus and Julius I may have thought that he could attract more converts to Christianity by allowing them to continue to celebrate on the same day. He may have also been influenced by the idea that Jesus had died on the anniversary of his conception; because Jesus died during Passover and, in the third century AD, Passover was celebrated on 25 March, he may have assumed that Jesus's birthday must have come nine months later, on 25 December.
Death and veneration
Julius I died in Rome on 12 April 352. He was succeeded by Liberius. Julius is venerated as a saint by the Catholic Church. His feast day is on 12 April.
