William IV, Duke of Jülich-Berg, was a nobleman who ruled in the late 15th and early 16th centuries. He was born in 1516 and became Duke in 1548, overseeing the territories of Jülich and Berg in what is now western Germany. His reign was marked by efforts to strengthen his duchy and navigate the complex political landscape of the Holy Roman Empire. William IV was known for his support of the Reformation and his attempts to balance the interests of various religious factions within his realm. He died in 1592, leaving a legacy of political maneuvering and cultural patronage that influenced the region's development.