Dag Hjalmar Agne Carl Hammarskjöld was born on July 29, 1905, in Jönköping, Sweden.  Serving as secretary-general of the United Nations from 1953 to 1961, he’s still considered one of the greatest diplomats in history.

Dag was the youngest of four sons born to Agnes and Hjalmar Hammarskjöld.  Hjalmar Hammarskjöld had served as prime minister of Sweden, member of the Hague Tribunal, governor of Uppland, and chairman of the board of the Nobel Foundation.

Hammarskjöld earned degrees in philosophy and law and worked as assistant secretary of the Unemployment Committee.  He served as a secretary on a governmental committee on unemployment from 1930 to 1934 and worked for Sweden’s central bank, Riskbank, from 1936 to 1948, spending several years as chairman of the bank’s general council.

Hammarskjöld entered public service in 1936, when he was appointed permanent undersecretary of the Swedish Ministry of Finance.  He held that post until 1945, when he was appointed as an advisor to the Cabinet on Financial and Economic Problems.  While in this office, Hammarskjöld was responsible for a series of trade and financial negotiations with countries from around the world.  He was then a delegate to the Organization for European Economic Cooperation from 1947 to 1953, cabinet secretary for the Ministry of Foreign Affairs from 1949 to 1951, and a government minister from 1951 to 1953.  Hammarskjöld was also part of the conference that established the Marshall Plan and headed the Swedish delegation at a meeting to promote economic partnership between the UK and Scandinavian countries.

After United Nations Secretary-General Trygve Lie announced his resignation in 1952, the UN met to select a replacement.  Hammarskjöld was among those under consideration and was a popular choice because he was considered “a brilliant economist, an unobtrusive technician, and an aristo-bureaucrat.”  The council voted on March 31, 1953 and Hammarskjöld received word of his nomination the following day.  He responded to the council, “With strong feeling personal insufficiency I hesitate to accept candidature, but I do not feel I could refuse to assume the task imposed on me should the Assembly follow the recommendation of the Security Council by which I feel deeply honoured.”

Hammarskjöld took the oath of office as secretary-general of the United Nations on April 10, 1953.  During the next eight years, he was responsible for the organization of the United Nations Emergency Force, the United Nations Observation Group in Lebanon, and the first and second International Conferences on the Peaceful Uses of Atomic Energy.  He also negotiated the release of 15 American pilots being detained by the People’s Republic of China.

These stamps were issued in 2001 for the 40th anniversary of Hammarskjöld’s death.

While on a peacekeeping trip to the newly liberated Congo, Hammarskjöld died in a plane crash on September 18, 1961.  The cause of the crash was never determined.  One inquiry found that the pilot had made an error, while another investigation claimed the plane was shot down by the KGB.

These Korea stamps were issued for Hammarskjöld’s 75th birthday

In July of 1997, the UN Security Council established the Dag Hammarskjöld Medal as a tribute to the sacrifice of those who had lost their lives during peace-keeping operations. The first Dag Hammarskjöld Medal was presented to his family.  Several buildings, schools, and streets have been named in Hammarskjöld’s honor.