(1905–61), Swedish diplomat and politician; full name Dag Hjalmar Agne Carl Hammarskjöld. As secretary general of the United Nations 1953–61, he was influential in the establishment of the UN emergency force in Sinai and Gaza 1956 and also initiated peace moves in the Middle East 1957–58. He was killed in a plane crash while on a peace mission in Congo. Nobel Peace Prize (1961, posthumously).