John I


Cause of Death:

523.08.13 to 526.05.18
Pope #53
St. Hormisdas (514-523)
St. Felix IV (526-530)

in Tuscany
526.05.18 in Ravenna
Illness and in prison at Ravenna
Pope John I


Born in Tuscany, central Italy. The son of Constantius.


In 525, Dionysius Exiguus, a Russian monk, was asked by Pope John to build him a calandar showing the exact dates of Easter for the next 100 years. Dionysius' calandar began with the birth of Christ, which Antipope Hippolytus (217-235) claimed without evidence, was December 25th. In response to skeptics, Dionysius argued that since it was "known" God created the earth on March 25th, the Son of God being perfect, must have been conceived on March 25th, making his birth 9 months later on December 25th. He also concluded that Christ must have died on March 25th.

December 25th was a civic holiday where Romans celebrated the birth of Mithras, the sun god. By 336, Christians participated by celebrating the birth of Christ. Christians in east however, celebrated it on January 6th.

New Years Day

Dionysius set the birth of Christ as 753 in the Roman year, and marked a week after, January 1st, 754 as "year one", calling it anno domini (the year of our Lord).


Died while in prison in Ravenna.

Rulers & Events:

493-526: King of Italy, Theodoric
518-527: Eastern Roman Emperor, Justin I
526-534: King of Italy, Athalaric