Although St. John I served as pope for only three years, he still had a big impact on the direction of the Church, the Diocese of Brooklyn said as it celebrated his feast day on Wednesday.

“Saint John I served as pope for about three years before he died of maltreatment at the hands of the emperor’s men,” the diocese posted on Facebook. “He had to face the Arian controversy and negotiate with the eastern part of the empire concerning the treatment of heretics.” 

St. John I, born in Tuscany, was noted for being a peacemaker and a martyr.

Although he was only an archdeacon at the time, he was elected Pope in the year 523.

Italy’s leader was Theodoric the Goth, who endorsed the Arian heresy, which denies the divinity of Christ. Theodoric appointed John to lead a delegation tasked with negotiating with Byzantine Emperor Justin I, something John wasn’t eager to do, yet he still fulfilled Theodoric’s directive, catholic.org says. Although scant details about the deal are known, John’s visit is cited as the main reason the schism between the Eastern and Western churches, which had been in place since 482, was bridged. 

The success, though, planted a seed of suspicion in Theodoric’s mind, because of John’s newfound friendly relationship with the other emperor, Franciscan Media says. Theodoric sent John to prison, and John died a short time later, possibly because of the treatment he received while incarcerated. John died just three years after becoming pope. 

St. John I is an example of a martyr, someone who chooses death over renunciation of faith, according to Britannica. His feast day is celebrated on May 18 because it is the anniversary of his death in 526.