Count John IV of Nassau-Siegen was a prominent nobleman in the 17th century, known for his military and political roles in Europe. Born in 1604, he was a member of the House of Nassau, a significant dynasty in the region. He served as a general in the Dutch Republic and played a crucial role in various military campaigns during the Eighty Years' War. In addition to his military career, John IV was also involved in the administration of his territories. He became the Count of Nassau-Siegen in 1640 and worked to strengthen his lands economically and politically. His leadership contributed to the stability and development of the region during a tumultuous period in European history.