John the Blind (Luxembourgish: Jang de Blannen; German: Johann der Blinde von Luxemburg; Czech: Jan Lucemburský) was the Count of Luxembourg from 1309 and King of Bohemia from 1310 and titular King of Poland. He was the eldest son of the Holy Roman Emperor Henry VII and his wife Margaret of Brabant. He is well known for having died while fighting in the Battle of Crécy at age 50, after having been blind for a decade.
Raised in Paris, John was French by education, but deeply involved in the politics of Germany. In 1310 his father arranged the marriage of the 14-year-old to Elisabeth from the Přemyslid dynasty, sister of the deceased King Wenceslaus III of Bohemia. The wedding took place in Speyer, after which the newlyweds made their way to Prague accompanied by a group led by the experienced diplomat and expert on Czech issues, Peter of Aspelt, Archbishop of Mainz. Because Henry had imperial regiments accompany and protect the couple from Nuremberg to Prague the Czech forces were able to gain control of Prague and depose the reigning King Henry of Carinthia on 3 December 1310.
Like his predecessor Henry, he was disliked by much of the Czech nobility. John was considered to be an "alien king" and gave up the administration of Bohemia after a while and embarked on a life of travel. He parted ways with his wife and left the Czech country to be ruled by the barons while spending time in Luxembourg and the French court.
At the Battle of Crécy in 1346 John controlled Phillip's advanced guard along with controlling the large contingents of Charles II of Alençon and Louis I, Count of Flanders. John was killed at age 50 while fighting against the English during the battle.
John was succeeded as King of Bohemia by his eldest son Charles (later Charles IV, Holy Roman Emperor). In Luxembourg, he was succeeded by his son by his second wife, Wenceslaus.