Count William II of Holland was a nobleman who ruled from 1256 until his death in 1257. He was the son of Count William I of Holland and Countess Adelaide of Cleves. His reign was marked by efforts to strengthen the power of the countship and to maintain peace in the region. William II was also known for his involvement in the politics of the Holy Roman Empire. He was elected King of the Romans in 1256, although he faced challenges in consolidating his authority. His untimely death led to a succession crisis, impacting the future of the County of Holland.