April 11

Mongol forces under Batu Khan defeat King Béla IV of Hungary at the Battle of Mohi.

Mongol forces under Batu Khan, a grandson of Genghis Khan, inflicted a crushing defeat on the army of King Béla IV of Hungary at the Battle of Mohi, opening much of Hungary to Mongol devastation. The Mongols withdrew from Europe the following year following the death of the Great Khan Ögedei, sparing the continent from further immediate conquest.

Franco-Ferrarese forces defeat a Holy League army at the Battle of Ravenna during the War of the League of Cambrai.

Combined French and Ferrarese forces defeated a Holy League army, including Spanish and papal troops, at the bloody Battle of Ravenna during the War of the League of Cambrai, though French commander Gaston de Foix was killed in the fighting. Despite the tactical victory, the heavy French losses and diplomatic pressures ultimately forced France to withdraw from Italy shortly afterward.

William III and Mary II are crowned as joint sovereigns of England, Scotland, and Ireland.

William III of Orange and his wife Mary II, daughter of the deposed King James II, were formally crowned as joint monarchs of England, Scotland, and Ireland following the Glorious Revolution. Their joint reign established important constitutional precedents limiting royal authority and affirming Parliament's role, developments later enshrined in the English Bill of Rights.

France and Great Britain sign the Treaty of Utrecht, helping bring an end to the War of the Spanish Succession.

Representatives of France, Great Britain, Spain, and other European powers signed the Treaty of Utrecht, a series of agreements that helped bring an end to the costly War of the Spanish Succession. The treaty significantly reshaped European and colonial territorial boundaries, including British gains in North America, and helped establish a new balance of power on the continent.

Johann Sebastian Bach premieres his "St Matthew Passion" at St. Thomas Church in Leipzig.

Johann Sebastian Bach premiered his "St Matthew Passion," an extensive and emotionally powerful musical setting of the Gospel account of Christ's crucifixion, at St. Thomas Church in Leipzig, where Bach served as music director. Largely forgotten after his death, the work was rediscovered and championed by composer Felix Mendelssohn a century later, helping spark a broader revival of interest in Bach's music.

American forces liberate the Buchenwald concentration camp in Germany.

American soldiers liberated the Buchenwald concentration camp near Weimar, Germany, discovering thousands of starving survivors along with horrific evidence of the systematic brutality and mass killing carried out by the Nazi regime. General Dwight Eisenhower personally toured the camp shortly afterward and ordered extensive documentation of the atrocities, believing future generations might otherwise refuse to believe such crimes had occurred.

President Harry Truman relieves General Douglas MacArthur of his command in Korea and Japan after public disagreements over war strategy.

President Harry Truman relieved General Douglas MacArthur of his command in Korea and Japan after MacArthur publicly and repeatedly challenged Truman's more cautious strategy for the Korean War, including MacArthur's calls to expand the conflict into China. The dramatic dismissal of a wildly popular wartime hero underscored the constitutional principle of civilian control over the U.S. military.

NASA launches Apollo 13 toward the Moon, a mission that would be aborted after an oxygen tank explosion.

NASA launched Apollo 13 toward the Moon, the third crewed lunar landing mission, but an oxygen tank aboard the spacecraft exploded two days later, forcing mission controllers and the crew into a harrowing improvised effort to bring the astronauts home safely without landing on the Moon. The mission's dramatic, ultimately successful rescue became one of NASA's most celebrated achievements despite failing its original objective.

Ugandan dictator Idi Amin is deposed as Tanzanian-backed forces capture the capital, Kampala.

Ugandan dictator Idi Amin, whose brutal eight-year rule had resulted in the deaths of hundreds of thousands of Ugandans, fled into exile as Tanzanian troops and Ugandan rebel forces captured the capital, Kampala, ending his regime. Amin spent the remainder of his life in exile, first in Libya and later Saudi Arabia, without ever facing trial for his government's atrocities.

Australia's men's national soccer team defeats American Samoa 31-0, setting a world record for the largest margin of victory in an international match.

Australia's men's national soccer team defeated American Samoa 31-0 in a World Cup qualifying match, setting a world record for the largest victory margin ever recorded in an official international football match. The lopsided result partly reflected American Samoa fielding an unusually young and inexperienced squad, and it later prompted debate about qualifying formats for smaller footballing nations.