May. 18 Tuesday of the Seventh Week of Easter; Optional Memorial of St. John I, pope and martyr, Opt. Mem.

John I was elected Pope in 523. The Arian King Theodoric sent him as his ambassador to Emperor Justin in Constantinople. On John I’s return, he was captured by the king, who was displeased at the outcome of the embassy and cast him into prison at Ravenna where he died a few days later. As pope he was responsible for introducing the Alexandrian computation of the date of Easter; it came to be accepted throughout the West.