William II of Avesnes was a notable nobleman in the 13th century, serving as the Count of Hainaut and Count of Holland. He was born around 1280 and became a significant political figure in the region, known for his efforts to strengthen his territories and maintain peace among local factions. His reign was marked by various conflicts and alliances, particularly with the House of Avesnes, which played a crucial role in the politics of the Low Countries. William II's leadership contributed to the consolidation of power in the region, influencing the future of Hainaut and Holland.