100% verified The same day, three eras.

17 September

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Contemporary era

1939

Soviet invasion of Poland

On 17 September 1939, the Soviet Union invaded eastern Poland.

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Contemporary era

1862

Battle of Antietam

On 17 September 1862, the Battle of Antietam was the bloodiest day of the American Civil War.

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From the Middle Ages to the Enlightenment

1787

US Constitution signed

On 17 September 1787, the Philadelphia Convention signed the US Constitution.

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