At that time [the year 336] Alexander presided over the church in Constantinople. He was a devout and godly bishop, qualities he clearly proved by his conflict with Arius. When Arius arrived in the city, the people divided into two factions and the city was thrown into confusion. Some insisted that the Creed of Nicaea must be obeyed, others argued that Arius' views were in harmony with reason. This forced Alexander into grave difficulties, especially since Eusebius of Nicomedia had violently threatened to have Alexander instantly deposed unless he admitted Arius and his disciples to holy communion.... At his wits' end, Alexander said farewell to the resources of human wisdom, and took refuge in God, devoting himself to continual fasting and ceaseless praying. Without telling anyone, he shut himself up in the church called "Peace", went up to the altar, and prostrated himself beneath the communion table, where he poured forth his fervent prayers with weeping. He did this without ceasing for many nights and days. And he received from God what he so earnestly sought; for this was his prayer: "If Arius's views are right, may I not be allowed to see the day appointed by the emperor for discussing them. But if I myself hold the true faith, may Arius suffer the penalty his ungodliness deserves, as the author of these evils...."
It was Saturday, and Arius was expecting to take communion with the church on the following day; but divine vengeance overtook his daring crimes. As he left the imperial palace, attended by a mob of Eusebius's followers like guards, he paraded proudly through the city, the centre of attention. But as he approached the place called Constantine's market, at one and the same time the terrors of conviction attacked his conscience, and a violent seizure attacked his bowels. He asked if there was somewhere nearby where he could relieve himself, and someone directed him to the back of the market. There he fainted, and his bowels came spilling out of his backside, together with streams of blood; parts of his spleen and liver poured out in the bloody flow. He died almost instantly. People in Constantinople still point out where this calamity happened, behind the meat-market in the colonnade; this constant pointing out of the place has preserved a perpetual memorial of this extraordinary death. The disaster filled with dread and alarm the party of Eusebius of Nicomedia; and the news spread quickly through the city and indeed the whole world. The emperor, growing more earnest in Christianity, confessed that God had vindicated the Creed of Nicaea, and rejoiced at what had happened.- N Needham, 2000 Years of Christ's Power