Henry III became King of France and Poland

Henry III (born on 19 September 1551 and died on 2 August 1589;aged 37) was a monarch of the House of Valois who was elected the monarch of the Polish-Lithuanian Common-wealth from 1573 to 1575 and ruled as King of France from 1574 until his death. He was the last French monarch of the Valois dynasty.

As the fourth son of King Henry II of France and Catherine de' Medici, Henry was not expected to assume the throne of France. He was thus a good candidate for the vacant Commonwealth throne, and he was elected with the dual titles King of Poland and Grand Duke of Lithuania. On 12 May 1588, when the Duke of Guise entered Paris, an apparently spontaneous Day of the Barricades erupted in favor of the Catholic champion. Henry III fled the city.