King Frederick IX of Denmark was born on March 11, 1899, and reigned from 1947 until his death in 1972. He was the son of King Christian X and Queen Alexandrine and became king after his brother, King George II, passed away. Frederick IX was known for his dedication to the Danish people and his efforts to modernize the monarchy. During his reign, Frederick IX supported various cultural and social initiatives, including the arts and education. He was also a naval officer and had a keen interest in maritime affairs. His reign saw Denmark's transition into a more modern constitutional monarchy, emphasizing democracy and social welfare.