On this day in 1683, Poland saved Europe from the expansion of Islam. Vienna, the capital of Austria, had been under siege by the Turks for two months when King John III Sobieski, leading a formidable Polish and Lithuanian army — supported by the Holy Roman Empire — advanced, broke the siege, and forced the Turks to retreat, halting what had until then been an unstoppable Islamic advance into Europe. This victory marked a turning point in the war between the Austrian Habsburgs and the Ottomans, who were gradually pushed back to the East, never to return.

In a letter sent to the Pope on this day, the Polish king wrote:

“By the grace of Heaven, the Crescent no longer triumphs over the Cross, and it has been torn down from the bell tower of St. Stephen’s in Vienna. To God, all the Glory!”