William I, Count of Hainaut

William I, called the Good (c. 1286–1337), was never meant to rule: after his brothers died in 1302–1303, he became count of Hainaut, Holland and Zeeland in 1304. That year Guy of Namur beat him at Duiveland and, with Brabant, overran most of Zeeland and Holland, but William recovered the lands and fought Flanders until the Peace of Paris in 1323, when Flanders renounced Zeeland and he gave up his claim to Imperial Flanders.

He occupied much of the Utrecht bishopric and annexed Amsterdam to Holland. In 1305 he married Joan of Valois, sister of the future Philip VI.

In 1326 he backed Queen Isabella's expedition against Edward II, and his daughter Philippa was betrothed to the future Edward III. In 1337 he joined Edward and others in a coalition against Philip VI, but died that year, succeeded by William II.