1909 – Born at Pantanaw on the 22nd of January.
1948 – He asked Thant to join him in Rangoon and appointed him as Director of Broadcasting.
1951-1957 – Thant was Secretary to the Prime Minister, writing speeches for U Nu, arranging his foreign travel, and meeting foreign visitors.
1955 – He also took part in a number of international conferences and was the secretary of the first Asian-African summit at Bandung, Indonesia which gave birth to the Non-Aligned Movement.
1961 – Serving as Acting Secretary-General on the 3rd of November, when he was unanimously appointed by the General Assembly, on the recommendation of the Security Council, to fill the unexpired term of Dag Hammarskjöld.
– He was appointed, the Soviet Union had tried to insist on a troika formula of three Secretaries-General, one representing each Cold War bloc, something which would have maintained equality in the United Nations between the superpowers.
1962 – He was then unanimously appointed Secretary-General by the General Assembly on the 30th of November for a term of office ending on the 3rd of November.
1966 – U Thant was re-appointed for a second term as Secretary-General of the United Nations by the General Assembly on the 2nd of December on the unanimous recommendation of the Security Council.
1967 – He was widely criticized in the US and Israel for agreeing to pull out UN troops in the Sinai in response to a request from Egyptian President Nasser.
1971 – On the 23rd of January, U Thant categorically announced that he would "under no circumstances" be available for a third term as Secretary-General.
1971 – His term of office continued on the 31st of December, when he retired.
1974 – Died of lung cancer in New York on the 25th of November.