William, count of Holland, 1227?–1256, German king (1254–56), previously rival king (1247–54) to Conrad IV. William was chosen by Pope Innocent IV to succeed Henry Raspe (d. 1247) as antiking to Conrad IV during the conflict between Innocent and Conrad's father, Holy Roman Emperor Frederick II. Although William was recognized as king by most of the German princes after Conrad's death (1254), his rule was only nominal and was never unchallenged. His major support came from the Rhenish towns. He was killed fighting the Frisians.