Duke John II, also known as John II of Denmark, was a significant historical figure who ruled as Duke of Schleswig and Holstein in the late 15th century. He was born in 1455 and became known for his efforts to strengthen the power of the duchies and improve their economic conditions. His reign was marked by political challenges and conflicts with neighboring territories. John II was a member of the House of Oldenburg, a royal family that played a crucial role in the history of Denmark and northern Europe. He died in 1513, leaving behind a legacy that influenced the future of the duchies and their relationship with the Danish crown.