June 15 events in history

923 Battle of Soissons: King Robert I of France is killed and King Charles the Simple is arrested by the supporters of Duke Rudolph of Burgundy
1184 King Magnus V of Norway is killed at the Battle of Fimreite
1215 King John of England puts his seal to the Magna Carta
1219 Northern Crusades: Danish victory at the Battle of Lyndanisse (modern-day Tallinn) establishes the Danish Duchy of Estonia. According to legend, this battle also marks the first use of the Dannebrog, the world's first national flag still in use, as the national flag of Denmark
1246 With the death of Duke Frederick II, the Babenberg dynasty ends in Austria
1300 The city of Bilbao is founded
1389 Battle of Kosovo: The Ottoman Empire defeats Serbs and Bosnians
1410 In a decisive battle at Onon River, the Mongol forces of Oljei Temur were decimated by the Chinese armies of the Yongle Emperor
1502 Christopher Columbus lands on the island of Martinique on his fourth voyage
1520 Pope Leo X threatens to excommunicate Martin Luther in papal bull Exsurge Domine
1580 Philip II of Spain declares William the Silent to be an outlaw
1648 Margaret Jones is hanged in Boston for witchcraft in the first such execution for the Massachusetts Bay Colony
1667 The first human blood transfusion is administered by Dr. Jean-Baptiste Denys
1752 Benjamin Franklin proves that lightning is electricity (traditional date, the exact date is unknown)
1775 American Revolutionary War: George Washington is appointed commander-in-chief of the Continental Army
1776 Delaware Separation Day: Delaware votes to suspend government under the British Crown and separate officially from Pennsylvania
1785 Jean-François Pilâtre de Rozier, co-pilot of the first-ever manned flight (1783), and his companion, Pierre Romain, become the first-ever casualties of an air crash when their hot air balloon explodes during their attempt to cross the English Channel
1804 New Hampshire approves the Twelfth Amendment to the United States Constitution, ratifying the document
1808 Joseph Bonaparte becomes King of Spain
1836 Arkansas is admitted as the 25th U.S. state
1844 Charles Goodyear receives a patent for vulcanization, a process to strengthen rubber
1846 The Oregon Treaty establishes the 49th parallel as the border between the United States and Canada, from the Rocky Mountains to the Strait of Juan de Fuca
1859 Pig War: Ambiguity in the Oregon Treaty leads to the "Northwestern Boundary Dispute" between United States and British/Canadian settlers
1864 American Civil War: The Second Battle of Petersburg begins
1864 Arlington National Cemetery is established when 200 acres (0.81 km2) around Arlington Mansion (formerly owned by Confederate General Robert E. Lee) are officially set aside as a military cemetery by U.S. Secretary of War Edwin M. Stanton
1867 Atlantic Cable Quartz Lode gold mine located in Montana
1877 Henry Ossian Flipper becomes the first African American cadet to graduate from the United States Military Academy
1878 Eadweard Muybridge takes a series of photographs to prove that all four feet of a horse leave the ground when it runs; the study becomes the basis of motion pictures
1888 Crown Prince Wilhelm becomes Kaiser Wilhelm II; he will be the last Emperor of the German Empire. Due to the death of his predecessors Wilhelm I and Frederick III, 1888 is the Year of the Three Emperors
1896 The deadliest tsunami in Japan's history kills more than 22,000 people
1904 A fire aboard the steamboat SS General Slocum in New York City's East River kills 1,000
1905 Princess Margaret of Connaught marries Gustaf, Crown Prince of Sweden
1909 Representatives from England, Australia and South Africa meet at Lord's and form the Imperial Cricket Conference
1913 The Battle of Bud Bagsak in the Philippines ends
1916 U.S. President Woodrow Wilson signs a bill incorporating the Boy Scouts of America, making them the only American youth organization with a federal charter
1919 John Alcock and Arthur Brown complete the first nonstop transatlantic flight when they reach Clifden, County Galway, Ireland
1920 Duluth lynchings in Minnesota
1920 A new border treaty between Germany and Denmark gives northern Schleswig to Denmark
1934 The U.S. Great Smoky Mountains National Park is founded
1936 First flight of the Vickers Wellington bomber
1937 A German expedition led by Karl Wien loses sixteen members in an avalanche on Nanga Parbat. It is the worst single disaster to occur on an 8000m peak
1940 World War II: Operation Ariel begins – Allied troops start to evacuate France, following Germany's takeover of Paris and most of the nation
1944 World War II: Battle of Saipan: The United States invade Japanese-occupied Saipan
1944 In the Saskatchewan general election, the CCF, led by Tommy Douglas, is elected and forms the first socialist government in North America
1945 The General Dutch Youth League (ANJV) is founded in Amsterdam, Netherlands
1954 UEFA (Union of European Football Associations) is formed in Basel, Switzerland
1970 Charles Manson goes on trial for the Sharon Tate murders
1972 Red Army Faction co-founder Ulrike Meinhof is captured by police in Langenhagen
1978 King Hussein of Jordan marries American Lisa Halaby, who takes the name Queen Noor
1985 Rembrandt's painting Danaë is attacked by a man (later judged insane) who throws sulfuric acid on the canvas and cuts it twice with a knife