What are the important events that happened on May 15? Here are historical events, facts, and some myths about this day.

May 15: Facts & Myths About This Day

May 15 is the 135^th day of the year 2025 in the Gregorian calendar. There are 230 days remaining until the end of this year. The day of the week is Thursday.

Under the Julian calendar, this day is May 2, 2025 – a Thursday. Both day of the week are the same but did you notice the difference with the Gregorian calendar?

When this day started, 1,747,267,200 seconds has elapsed since midnight of January 1, 1970 – the Unix epoch.

Strange as it may, if we name this day after a polygon then it will be called ‘hectatriacontapentagon’ day.

Taurus is the zodiac sign of a person born on this day. Emerald is the modern birthstone for this month. Sapphire is the mystical birthstone from Tibetan origin that dates back over a thousand years.

According to the lunisolar Chinese calendar, there are 278 days remaining before the start of the next Chinese New Year.

The ancient Maya civilization believes that the end of the world will happen on December 21, 2012. There are now 4,528 days since this fabled cataclysmic event.

May 15 Historical Events

• 1648 –
  The Treaty of Westphalia signed.
• 1817 –
  Opening of the first private mental health hospital in the United States, the Asylum for the Relief of Persons Deprived of the Use of Their Reason (now Friends Hospital) in Philadelphia, Pennsylvania.
• 1829 –
  The Aaronic Priesthood is restored to Joseph Smith Jr. and Oliver Cowdery, prior to the organization of the Church of Jesus Christ of Latter-day Saints.
• 1836 –
  Francis Baily observes “Baily’s beads” during an annular eclipse.
• 1905 –
  Las Vegas, Nevada, is founded when 110 acre, in what later would become downtown, are auctioned off.
• 1911 –
  In Standard Oil Co. of New Jersey v. United States, the United States Supreme Court declares Standard Oil to be an “unreasonable” monopoly under the Sherman Antitrust Act and orders the company to be broken up.
• 1928 –
  Mickey Mouse premiered in his first cartoon, Plane Crazy
• 1945 –
  World War II: The final skirmish in Europe is fought near Prevalje, Slovenia.
• 1987 –
  The Soviet Union launches the Polyus prototype orbital weapons platform. It fails to reach orbit.
• 2008 –
  California becomes the second U.S. state after Massachusetts in 2004 to legalize same-sex marriage after the state’s own Supreme Court rules a previous ban unconstitutional.

Who were born on May 15?

• 1720 –
  Maximilian Hell, Slovakian astronomer (d. 1792)
• 1862 –
  Arthur Schnitzler, Austrian dramatist (d. 1931)
• 1890 –
  Katherine Anne Porter, American author (d. 1980)
• 1936 –
  Ralph Steadman, British cartoonist
• 1938 –
  Diane Nash, American Civil Rights Movement figure
• 1941 –
  K.T. Oslin, American musician
• 1947 –
  Graeham Goble, Australian musician and record producer (Little River Band)
• 1959 –
  Kaokor Galaxy, Thai boxer
• 1961 –
  Melle Mel, American musician
• 1970 –
  Ronald de Boer, Dutch football player

Who died on May 15?

• 1585 –
  Niwa Nagahide, Japanese warlord (b. 1535)
• 1886 –
  Emily Dickinson, American poet (b. 1830)
• 1924 –
  Paul-Henri-Benjamin d'Estournelles de Constant, French diplomat, recipient of the Nobel Peace Prize (b. 1852)
• 1940 –
  Menno ter Braak, Dutch author and polemicist (b. 1902)
• 1956 –
  Austin Osman Spare, British artist and magician (b. 1886)
• 1967 –
  Edward Hopper, American painter (b. 1882)
• 1978 –
  Sir Robert Menzies, twelfth Prime Minister of Australia (b. 1894)
• 1991 –
  Andreas Floer, German mathematician (b. 1956)
• 1995 –
  Eric Porter, British actor (b. 1928)
• 2008 –
  Tommy Burns, Scottish footballer (b. 1956)