STAVANGER, Norway — King Harald V of Norway, who went into exile in the United States as a child during the Nazi occupation of his homeland and refused a string of European noblewomen to marry his school sweetheart, died Friday. He was 89. The palace said he died at the National Hospital in Oslo at 6:35 a.m. Harald was Europe’s oldest monarch. The popular king modernized the royal house but refused to follow in the footsteps of other aging monarchs who have abdicated in recent times. His son automatically became King Haakon VIII. Like other royal houses in Europe, the Norwegian monarchs serve a largely symbolic role, enjoying celebrity status while real power in the democracy of 5.5 million rests with an elected parliament. Harald was crowned after his British-born father, King Olav V, died in January 1991, and reigned during an oil-and-gas-driven economic boom in his country. “A whole nation is in mourning and the people of Norway are left with a deep sense of gratitude for a long life in the service of Norway,” Prime Minister Jonas Gahr Støre said in a statement. “For more t