September 9: National Grandparents' Day in the United States (2007); Republic Day in North Korea, Independence Day in Tajikistan.
- 1513 – War of the League of Cambrai: King James IV of Scotland (pictured) was killed at the Battle of Flodden Field in Northumberland while leading an invasion of England.
- 1850 – As part of the Compromise of 1850, California was admitted into the United States as a free state instead of a slave state where slavery was legal.
- 1971 – Prisoners rioted and seized control of the Attica Correctional Facility in Attica, New York, USA, taking thirty-three guards hostage. The uprising ended four days later after state police and guards raided the prison, leaving almost 40 hostages and inmates dead from the ensuing gunfire.
- 2001 – Ahmad Shah Massoud, leader of the Northern Alliance, was assassinated in Afghanistan.
- 2004 – A car bomb exploded outside the Australian embassy in Jakarta, Indonesia, killing at least nine people and injuring over 150 others.
More events on this day... Recent days: September 8 – September 7 – September 6
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