William III or II (died after 1037) was the Count and Margrave of Provence from 1014 to his death. He inherited his titles from his father Rotbold III. His mother was Ermengard, later the second wife of Rudolph II of Burgundy. He is recorded as late as 1032 with the title of marchio and is last recorded donating property to Cluny in 1037. He married Lucia, but had no known descendants, leaving his margravial rights to his cousin.
Sources
- Foundation for Medieval Genealogy: Provence.
- Lewis, Archibald R. The Development of Southern French and Catalan Society, 718–1050. University of Texas Press: Austin, 1965.
