William II, Count of Hainaut
William II (1307 – 26 September 1345) was Count of Hainaut from 1337 until his death. He was also Count of Holland (as William IV) and Count of Zeeland. He succeeded his father, Count William I of Hainaut. While away fighting in Prussia, the Frisians revolted. William returned home and at the Battle of Warns, he was killed.