480 BC - The Battle of Thermopylae, fought between 300 Spartans, led by their king, Leonidas, and the Achaemenid Empire begins.
1630 - The city of Boston, Massachusetts is founded.
1775 - In the American Revolutionary War, the invasion of Canada begins with the Siege of Fort St. Jean.
1787 - The United States Constitution is signed in Philadelphia, Pennsylvannia.
1814 - Francis Scott Key finishes his poem "Defense of Fort McHenry", later to be the lyrics of "The Star Spangled Banner".
1862 - George B. McClellan halts the northward drive of Robert E. Lee's Confederate army in the single day Battle of Antietam. With a total of 23,000 lives lost it remains the bloodiest day in American history.
