King Harald V of Norway has died at the age of 89, the Norwegian Royal Palace announced. He died at the National Hospital in Oslo at 6:35 a.m. on Friday.

Harald, who became king in 1991, was Europe’s oldest reigning monarch and served for more than three decades. He was widely credited with modernising the Norwegian monarchy while maintaining its largely ceremonial role.

Born in 1937, Harald was three years old when Nazi Germany occupied Norway during World War II. He fled to the United States with his mother and sisters, while his father and grandfather went into exile in Britain. The royal family returned to Norway in 1945.

A passionate sailor and former Olympian, Harald married his longtime sweetheart, Sonja Haraldsen, in 1968 after initially facing opposition to the union because she was a commoner. They had two children, Crown Prince Haakon and Princess Märtha Louise.

During his reign, Harald became known for his advocacy of democracy, diversity, religious tolerance and LGBTQ+ rights. He was particularly praised for his response to the 2011 terrorist attacks in Norway, when he called for an open and inclusive society.

Prime Minister Jonas Gahr Støre described Harald as a monarch who demonstrated an “unwavering faith” in the Norwegian people and served the country with distinction.

Harald, who had experienced several health problems in recent years, had remained committed to his role and previously said his oath to the Norwegian throne was for life. His son succeeds him as King Haakon VIII.