January 1 – On This Day - RealLife Debates

1801 – The legislative union of Great Britain and Ireland comes into effect, creating the United Kingdom of Great Britain and Ireland. (britannica.com)
1863 – U.S. President Abraham Lincoln issues the Emancipation Proclamation, declaring all slaves in Confederate states to be free. (history.com)
1901 – The Commonwealth of Australia is officially established as the six colonies federate into one nation. (en.wikipedia.org)
1959 – Cuban revolutionary leader Fidel Castro comes to power after the overthrow of Fulgencio Batista. (britannica.com)

J. Edgar Hoover — 1895–1972 — First Director of the Federal Bureau of Investigation (FBI) of the United States. (britannica.com)
Verne Troyer — 1969–2018 — American actor, best known for playing Mini-Me in the Austin Powers films. (en.wikipedia.org)
Grandmaster Flash — 1958 — Influential American hip-hop DJ and pioneer in turntablism. (britannica.com)

New Year’s Day — Celebrated worldwide as the first day of the Gregorian calendar year. Traditions include fireworks, countdowns, resolutions, and cultural ceremonies. (en.wikipedia.org)
Solemnity of Mary, Mother of God — A Roman Catholic feast day observed on January 1. (vatican.va)