The birthday of King Harald V of Norway is observed in Norway on February 21, marking an official flag flying day throughout the country. On this occasion, the state flag of Norway is required to be flown by all branches of government and state agencies. King Harald V was born on February 12, 1937, and became Crown Prince in 1957 when his father ascended the throne. He married Sonja Haraldsen in 1968, a union that generated significant public interest due to her status as a commoner. Harald succeeded to the throne on January 17, 1991, and was consecrated later that year. As the formal head of the Norwegian Armed Forces and the Church of Norway, his role is primarily ceremonial within Norway's parliamentary constitutional monarchy. King Harald and Queen Sonja have two children, Crown Prince Haakon and Princess Märtha Louise.