The twenty-seventh day of November.
- 1095: Pope Urban II declares the First Crusade at the Council of Clermont.
- 1983: The code of canon law is updated; CIC1983 comes into force, superseding CIC1917 and incorporating the reforms of the Second Vatican Council.
- 2004: Pope John Paul II returns the relics (bones) of two patriarchs of Constantinople, John Chrysostom and Gregory Nazianzen, to Istanbul. Crusaders had plundered the relics and transported them to Rome in 1204.