Saint William of York, (late 11th century - 8 June 1154) also known as William FitzHerbert, William I FitzHerbert and William of Thwayt, was an English priest and Archbishop of York. William FitzHerbert has the unusual distinction of having been Archbishop of York twice, both before and after his rival Henry Murdac. He was a relative of King Stephen of England, and the king helped secure FitzHerbert's election to York after a number of candidates had failed to secure papal confirmation. FitzHerbert faced opposition from the Cistercians who, after the election of the Cistercian Pope Eugenius III, managed to have the archbishop deposed in favor of the Cistercian Murdac. From 1147 until 1153, FitzHerbert worked to secure his restoration to York, which he finally achieved after the deaths of both Murdac and Eugenius. He did not retain the see long, as he died shortly after returning to York, allegedly having been poisoned. After St William's death miracles were reported at his tomb from the year 1177 onwards, and in the year 1226 he was declared a saint.
St William's feast day is celebrated on 8 June, the day of his death, although his veneration is largely localized to York. Traditional iconography and windows often depict St William's crossing of the Tweed; some iconography shows him crossing in a boat. His remains were rediscovered in the 1960s and are now in the crypt at York Minster.