The first day of January.
- 1001: Grand Prince Stephen I of Hungary is named the first King of Hungary by Pope Silvester II.
- 1700: Russia numbers its years from Christ instead of Creation.
- 1802: Thomas Jefferson's reply to the Danbury Baptist Association establishes "the wall of seperation between church and state."
- 1935: Archbishop Cesare Orsenigo pays a courtesy call to Adolph Hitler. (The Roman Catholic Church was officially neutral during World War II).
- 1964: The National Evangelical Lutheran Church, a historically Finnish American church, merges with the Lutheran Church - Missouri Synod, a historically German American church.
- 1966: Pope Paul VI decalares a jubilee, urging all Catholics to study and accept the decisions of the Second Vatican Council and apply them in spiritual renewal.
- 1971: Pope Paul VI's motu proprio Ingravescentem Aetatem goes into effect, denying a vote in papal elections to cardinals over the age of 80.
- 1988: The Lutheran Church in America, the American Lutheran Church and the Association of Evangelical Lutheran Churches merge into the Evangelical Lutheran Church in America.
- The seventh day of Christmas (and eighth night of same).
- Feast of the Circumcision of Christ (Old calendar).
- Holy Day of Obligation in many countries.
- Solemnity of Mary, Mother of God (New calendar).
- Fulgentius of Ruspe
- Odilo of Cluny
- Feast of the Holy Name of Jesus
- Feast of the Circumcision of Christ
- Saint Basil the Great, Archbishop of Caesarea in Cappadocia (379)
- Martyr Basil of Ancyra (362)
- Saint Fulgentius of Ruspe, Bishop of Ruspe in North Africa
- Martyr Theodotus
- Saint Gregory of Nazianzus the Elder, bishop and father of Saint Gregory the Theologian (374)
- Saint Theodosius of Tryglia, abbot
- Martyr Peter of the Peloponnesus (1776)
- New martyrs Platon of Revel, bishop, priest Michael, and priest Nicholas in Estonia (1919)