Duke Friedrich of Schleswig was a nobleman from the House of Oldenburg, a prominent royal family in Northern Europe. He was born in the late 15th century and became Duke of Schleswig in 1523. His reign was marked by efforts to strengthen the duchy's position within the Holy Roman Empire. Friedrich was known for his political alliances and military engagements, particularly in relation to the Danish crown. His leadership contributed to the complex history of Schleswig and its ties to both Denmark and Germany. He played a significant role in the regional power dynamics of his time.