June 27

Pope Agatho is consecrated as head of the Catholic Church.

Pope Agatho was consecrated as head of the Catholic Church, later convening an important church council that condemned the monothelite heresy regarding the nature of Christ, a theological dispute that had significantly strained relations between the Western and Eastern branches of Christianity.

Explorer Amerigo Vespucci sights the coast of present-day Brazil during his voyage along the South American coastline.

Italian explorer Amerigo Vespucci, sailing on a Portuguese-sponsored expedition along the South American coastline, sighted the coast of present-day Brazil during a voyage that helped convince European geographers the newly encountered lands were an entirely separate continent rather than part of Asia. His published accounts of these explorations later led to the New World continents being named in his honor.

King George II leads British forces into battle at Dettingen, the last time a reigning British monarch personally commanded troops in combat.

King George II of Britain personally led his troops into battle against French forces at the Battle of Dettingen during the War of the Austrian Succession, becoming the last reigning British monarch to command troops in person on a battlefield, a practice increasingly seen as impractical for subsequent constitutional monarchs.

A mob murders Mormon leader Joseph Smith and his brother Hyrum at a jail in Carthage, Illinois.

A mob stormed the jail in Carthage, Illinois, where Mormon founder Joseph Smith and his brother Hyrum were being held, and shot both men to death, a killing that plunged the young religious movement into a succession crisis eventually resolved when Brigham Young assumed leadership and led followers west to Utah.

Union and Confederate forces clash at the Battle of Kennesaw Mountain during the Atlanta Campaign of the Civil War.

Union and Confederate forces clashed in a costly and unsuccessful Union frontal assault against heavily fortified Confederate positions at the Battle of Kennesaw Mountain during General William Tecumseh Sherman's Atlanta Campaign. The rare tactical setback resulted in significant Union casualties, though it did little to slow Sherman's steadily advancing broader offensive through Georgia toward Atlanta.

Joshua Slocum completes the first solo circumnavigation of the globe by sea.

American sailor Joshua Slocum completed the first successful solo circumnavigation of the globe by sea, returning to Newport, Rhode Island, after a roughly three-year voyage aboard his small sloop Spray, an achievement that established him as a pioneering figure in solo ocean sailing.

Sailors mutiny aboard the Russian battleship Potemkin, an uprising later dramatized in Sergei Eisenstein's famous film.

Sailors aboard the Russian battleship Potemkin mutinied against their officers over grievances including spoiled, maggot-infested meat and harsh military discipline, part of the broader wave of unrest sweeping the Russian Empire during the 1905 Revolution. The dramatic uprising was later immortalized in Sergei Eisenstein's influential 1925 silent film "Battleship Potemkin," celebrated for its groundbreaking editing techniques.

Palestinian and German militants hijack Air France Flight 139, diverting it to Entebbe, Uganda, leading to a dramatic Israeli rescue raid days later.

Palestinian and German militants hijacked Air France Flight 139 and diverted it to Entebbe, Uganda, where Israeli commandos later conducted a daring long-distance rescue raid freeing most of the hostages, an operation widely regarded as one of the most successful counterterrorism missions in history.

Yugoslav federal forces invade Slovenia, beginning the brief Ten-Day War.

Forces of the Yugoslav People's Army invaded the recently seceded republic of Slovenia, beginning the brief Ten-Day War, a relatively low-casualty conflict that nonetheless marked the violent start of Yugoslavia's disintegration. Slovenian territorial defense forces successfully resisted the invasion, and an internationally brokered ceasefire led to the withdrawal of federal troops within weeks.

Tony Blair resigns as British prime minister after a decade in office, succeeded by Gordon Brown.

Tony Blair resigned as British prime minister after a decade in office marked by significant domestic reforms and the deeply controversial decision to join the U.S.-led invasion of Iraq, handing power to his longtime chancellor and political ally Gordon Brown.