January 15 is the fifteenth day of the year in the Gregorian calendar. 350 days (351 in leap years) remain in the year after this day.
69 - Otto becomes Roman emperor, but remains in power for only three months.
1535 - King Henry VIII of England assumes supremacy over the Church of England under a charter previously adopted by the English Parliament.
1559 - Elizabeth Tudor, daughter of Henry VIII and Anne Bohlen, is crowned at Wesminster Cathedral in London as Elizabeth I, one of the most important rulers in English history. She ascended the throne after the death of Queen Mary I.
1582 - Poland and Russia, with the mediation of Pope Gregory XIII, sign a peace treaty by which Russia loses access to the Baltic Sea.
1804 - Janissary elders, dahis, who usurped power in the Belgrade pashaluq in 1801, begin the "slaughter of princes" in an attempt to prevent the rebellion of the Serbian people against janissary tyranny. About 70 most prominent Serbian princes, prominent people and clergymen were caught and executed for fraud, including Aleksa Nenadović, Ilija Birčanin, Hadži Ruvim and Hadži Đera. That event accelerated the outbreak of the First Serbian Uprising.
1895 - The ballet "Swan Lake" by Pyotr Ilyich Tchaikovsky is premiered in St. Petersburg in its final version, in which it is still performed today.
1910 - French Congo becomes part of French Equatorial Africa.
1912 - Propaganda leaflets are thrown from a plane for the first time during the Italo-Turkish War.
1919 - Freikors assassinate leaders of the German labor movement Rosa Luxemburg and Karl Liebknecht in Berlin after a failed uprising.
1920 - Prohibition (Walsted's law) is introduced in the United States with the adoption of the 18th Amendment to the US Constitution.
1943 - US troops in World War II push the Japanese off the Pacific island of Guadalcanal, halting their advance toward Australia.
1943 - The Pentagon, the world's largest administration building, houses the US Department of Defense in Arlington, Virginia, near Washington.
1945 - The Italian news agency ANSA is founded.
1970 - Muammar al-Gaddafi becomes Libya's prime minister.
1970 - Biafra surrenders after 32 months of fighting for independence from Nigeria.
1971 - Presidents of Egypt and the Presidium of the Supreme Soviet of the USSR Anwar el Sadat and Nikolai Podgor�