Portal:Belgium/Anniversaries/September/September 17
- 1322: death of Robert III of Flanders, nicknamed "The Lion of Flanders", Count of Flanders
- 1665: death of Philip IV of Spain, King of Spain and ruler over most of the current territory of Belgium
- 1679: death of John of Austria the Younger, Governor of the Habsburg Netherlands
- 1903: birth of George Koltanowski, holder of the world record for most simultaneous blindfolded chess games
- 1964: death of Jean Ray, writer, also known as John Flanders, best known for his numerous fantastique works
- 1999: death of Henri Storck, documentary film director