6 September

3114 BC – According to the proleptic Julian calendar the current era in the Maya Long Count Calendar started. (Non-standard interpretation)
394 – Battle of the Frigidus: The Christian Roman Emperor Theodosius I defeats and kills the pagan usurper Eugenius and his Frankish magister militum Arbogast.
1492 – Christopher Columbus sails from La Gomera in the Canary Islands, his final port of call before crossing the Atlantic for the first time.
1522 – The Victoria, the only surviving ship of Ferdinand Magellan's expedition, returns to Sanlúcar de Barrameda in Spain, becoming the first ship to circumnavigate the world.
1620 – The Pilgrims sail from Plymouth, England, on the Mayflower to settle in North America. (Old Style date; September 16 per New Style date.)
1628 – Puritans settle Salem, which will later become part of Massachusetts Bay Colony.
1634 – Thirty Years' War: In the Battle of Nördlingen the Catholic Imperial army defeats Protestant armies of Sweden and Germany.
1781 – The Battle of Groton Heights takes place, resulting a British victory.
1847 – Henry David Thoreau leaves Walden Pond and moves in with Ralph Waldo Emerson and his family in Concord, Massachusetts.
1861 – American Civil War: Forces under Union General Ulysses S. Grant bloodlessly capture Paducah, Kentucky, which gives the Union control of the mouth of the Tennessee River.
1863 – American Civil War: Confederates evacuate Battery Wagner and Morris Island in South Carolina.
1870 – Louisa Ann Swain of Laramie, Wyoming becomes the first woman in the United States to cast a vote legally after 1807.
1885 – Eastern Rumelia declares its union with Bulgaria. The Unification of Bulgaria is accomplished.
1888 – Charles Turner becomes the first bowler to take 250 wickets in an English season – a feat since accomplished only by Tom Richardson (twice), J.T. Hearne, Wilfred Rhodes (twice) and Tich Freeman (six times).
1901 – Anarchist Leon Czolgosz shoots and fatally wounds US President William McKinley at the Pan-American Exposition in Buffalo, New York.
1930 – Democratically elected Argentine president Hipólito Yrigoyen is deposed in a military coup.
1937 – Spanish Civil War: The start of the Battle of El Mazuco.
1939 – World War II: The Battle of Barking Creek.
1939 – World War II: South Africa declares war on Germany.
1940 – King Carol II of Romania abdicates and is succeeded by his son Michael.
1943 – The Monterrey Institute of Technology, one of the largest and most influential private universities in Latin America, is founded in Monterrey, Mexico.
1944 – World War II: The city of Ypres, Belgium is liberated by allied forces.
1948 – Juliana becomes Queen of the Netherlands.
1949 – Allied military authorities relinquish control of former Nazi Germany assets back to German control.
1949 – A former sharpshooter in World War II, Howard Unruh kills 13 neighbors in Camden, New Jersey, with a souvenir Luger to become the first U.S. single-episode mass murderer.
1952 – Canada's first television station, CBFT-TV, opens in Montreal.
1955 – Istanbul Pogrom: Istanbul's Greek and Armenian minority are the target of a government-sponsored pogrom.
1963 – The Centre for International Industrial Property Studies (CEIPI) is founded.
1965 – War of 1965: India retaliates following Pakistan's Operation Grand Slam which resulted in the Indo-Pakistani War of 1965 that ends in a stalemate and follows the signing of the Tashkent Declaration.
1966 – In Cape Town, South Africa, the architect of Apartheid, Prime Minister Hendrik Verwoerd, is stabbed to death during a parliamentary meeting.
1968 – Swaziland becomes independent.
1970 – Two passenger jets bound from Europe to New York are simultaneously hijacked by Palestinian terrorist members of PFLP and taken to Dawson's Field in Jordan.
1972 – Munich Massacre: 9 Israel athletes taken hostage at the Munich Olympic Games by the Palestinian "Black September" terrorist group died (as did a German policeman) at the hands of the kidnappers during a failed rescue attempt. 2 other Israeli athletes are slain in the initial attack the previous day.
1976 – Cold War: Soviet air force pilot Lt. Viktor Belenko lands a MiG-25 jet fighter at Hakodate on the island of Hokkaidō in Japan and requests political asylum in the United States.
1983 – The Soviet Union admits to shooting down Korean Air Flight KAL-007, stating that the pilots did not know it was a civilian aircraft when it violated Soviet airspace.
1985 – Midwest Express Airlines Flight 105, a Douglas DC-9 crashes just after takeoff from Milwaukee, Wisconsin, killing 31.
1986 – In Istanbul, two terrorists from Abu Nidal's organization kill 22 and wound six inside the Neve Shalom synagogue during Shabbat services.
1991 – The Soviet Union recognizes the independence of the Baltic states: Estonia, Latvia and Lithuania.
1991 – The name Saint Petersburg is restored to Russia's second largest city, which had been renamed Leningrad in 1924.
1992 – Hunters discover the emaciated body of Christopher Johnson McCandless at his camp 20 miles (32 km) west of the town of Healy, Alaska.
1995 – Cal Ripken Jr of the Baltimore Orioles plays in his 2,131st consecutive game, breaking a record that stood for 56 years.
1997 – Funeral of Diana, Princess of Wales takes place in London. Over a million people lined the streets and 2.5 billion watched around the world on television.
2008 – Turkish President Abdullah Gül attends an association football match in Armenia after an invitation by Armenian President Serzh Sarkisyan; he is the first Turkish head of state to visit the country.
2009 – The ro-ro ferry SuperFerry 9 sinks off the Zamboanga Peninsula in the Philippines with 971 persons aboard; all but ten are rescued.

Holidays and observances

Armed Forces Day (São Tomé and Príncipe)
Christian Feast Days:
Begga
Chagnoald
Gondulphus of Metz
September 6 (Eastern Orthodox liturgics)
Defence Day or Army Day (Pakistan)
Flag Day (Bonaire)
Independence Day, celebrates the independence of Swaziland from the United Kingdom in 1968
Stillbirth Remembrance Day (several U.S. states and Canadian provinces)
Unification Day (Bulgaria)