Pope John Paul II established World Youth Day, an event for young Christians around the world.
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Pope Gregory XIII introduced the concept of the Gregorian Calendar to Europe.
Pope Constantine died.
Henry VIII declared his marriage to Catherine of Aragon officially null and void, despite Pope Clement VII's refusal to allow it.
Saint John I became the Catholic Pope.
The Trevi Fountain, one of Rome's most famous landmarks, was opened to the public by Pope Clement XIII.
