May 16

Baldwin IX of Flanders is crowned as the first emperor of the Latin Empire, established after the Fourth Crusade's sack of Constantinople.

Baldwin IX, Count of Flanders, was crowned as the first emperor of the newly established Latin Empire, the crusader state created in the aftermath of the Fourth Crusade's controversial sack of Constantinople, ruling over fractured former Byzantine territory that proved difficult to govern and defend against surrounding rivals.

Florence expels the ruling Medici family and re-establishes itself as a republic.

Florentine citizens rose up and expelled the ruling Medici family from the city, re-establishing Florence as an independent republic amid the broader turmoil of the ongoing Italian Wars and the sack of Rome weeks earlier, though Medici rule would eventually be forcibly restored years later with foreign military support.

Sir Thomas More resigns as Lord Chancellor of England amid tensions over King Henry VIII's break with the Catholic Church.

Sir Thomas More resigned as Lord Chancellor of England, citing failing health but privately unwilling to publicly support King Henry VIII's break with the Roman Catholic Church over his divorce from Catherine of Aragon, a principled stand of conscience that led to More's eventual trial and execution for treason five years later.

The future Marie Antoinette marries the Dauphin of France, later King Louis XVI, in a proxy ceremony sealing a Franco-Austrian alliance.

The fourteen-year-old Archduchess Marie Antoinette of Austria married the fifteen-year-old Dauphin of France, the future King Louis XVI, in a lavish proxy ceremony held at Versailles intended to cement a diplomatic alliance between the rival Habsburg and Bourbon royal houses following centuries of conflict.

The U.S. Senate falls one vote short of convicting President Andrew Johnson in his impeachment trial.

The U.S. Senate fell one single vote short of the two-thirds majority required to convict President Andrew Johnson on impeachment charges stemming from his defiant removal of a cabinet secretary, narrowly allowing him to remain in office and avoid becoming the first American president ever removed from power.

Britain and France sign the secret Sykes-Picot Agreement, outlining plans to partition Ottoman territories in the Middle East.

British and French diplomats Mark Sykes and François Georges-Picot secretly negotiated and signed the Sykes-Picot Agreement, outlining how the two powers would divide and administer former Ottoman territories across the Middle East after World War I, decisions whose lasting consequences continue to shape regional borders and politics today.

Pope Benedict XV canonizes Joan of Arc, nearly 500 years after her execution.

Pope Benedict XV formally canonized Joan of Arc as a saint of the Catholic Church, nearly five centuries after English authorities burned her at the stake as a convicted heretic in 1431, reflecting a dramatic historical rehabilitation of her legacy that had begun with a formal retrial and exoneration decades after her death.

The first Academy Awards ceremony is held in Hollywood, honoring films from the previous two years.

The first Academy Awards ceremony was held in a brief, private banquet at the Hollywood Roosevelt Hotel, honoring films released over the previous two years with a ceremony lasting only about fifteen minutes, a modest beginning for what became the film industry's most prestigious and closely watched annual televised awards event.

British bombers carry out Operation Chastise, the famous "Dambusters" raid targeting German dams in the Ruhr Valley.

Royal Air Force bombers of the specially formed No. 617 Squadron carried out the daring "Dambusters" raid, using specially designed spinning bouncing bombs developed by engineer Barnes Wallis to breach hydroelectric dams in Germany's industrial Ruhr Valley, causing significant flooding and disruption at a heavy cost to the attacking aircrews.

Physicist Theodore Maiman successfully operates the first working laser at Hughes Research Laboratories.

Physicist Theodore Maiman successfully operated the world's first working laser, using a ruby crystal as the lasing medium, at Hughes Research Laboratories in California, a breakthrough that launched an entirely new field of technology with wide-ranging applications later spanning medicine, telecommunications, manufacturing, and consumer electronics.