William III of Montferrat was a nobleman who lived during the late 12th and early 13th centuries. He was a member of the House of Montferrat, a prominent family in northern Italy. William became the Margrave of Montferrat in 1191 and played a significant role in the political landscape of the region, often engaging in alliances and conflicts with neighboring territories. His reign was marked by efforts to strengthen his family's influence and secure their lands. William III was also involved in the Crusades, participating in military campaigns aimed at reclaiming the Holy Land. His leadership contributed to the legacy of the Montferrat family in medieval European history.