Count John II of Nassau-Siegen was a nobleman from the House of Nassau, born in 1604. He is best known for his role as a military leader during the Thirty Years' War, where he served in various capacities, including as a general. His leadership was marked by his efforts to defend the interests of his territories in the Holy Roman Empire. In addition to his military career, John II was also a patron of the arts and education. He established the Siegen University and supported cultural initiatives in his region. His contributions helped shape the cultural landscape of Nassau-Siegen during the 17th century.