Wikipedia:Selected anniversaries/September 17
- 1176 – Byzantine–Seljuq wars: Seljuq Turks prevented Byzantine forces from taking the interior of Anatolia at the Battle of Myriokephalon in Phrygia.
- 1630 – Puritans of the Massachusetts Bay Colony founded the city of Boston.
- 1970 – The Jordanian army entered Amman as part of operations to oust Palestinian fedayeen from the country in what became known as Black September (smoke over Amman pictured).
- 1980 – Solidarity, a Polish trade union, was founded as the first independent labor union in an Eastern Bloc country.