Title: Truman Day
Content:  Harry S. Truman (May 8, 1884 – December 26, 1972) was the 33rd President of the United States (1945–1953), an American politician of the Democratic Party. He served as a United States Senator from Missouri (1935-1945) and briefly as Vice President (1945) before he succeeded to the presidency on April 12, 1945 upon the death of Franklin D. Roosevelt. He was president during the final months of World War II, making the decision to drop the atomic bomb on Hiroshima and Nagasaki. Truman was elected in his own right in 1948. He presided over an uncertain domestic scene as America sought its path after the war, and tensions with the Soviet Union increased, marking the start of the Cold War.
Title: Presidency of Harry S. Truman
Content:  Harry S. Truman's tenure as the 33rd president of the United States began on April 12, 1945, when Truman became president on his predecessor's death, and ended on January 20, 1953. He had been vice president for only 8170 days days when he succeeded to the presidency upon the death of Franklin D. Roosevelt. A Democrat from Missouri, he ran for and won a full four–year term in the 1948 election. Although exempted from the newly-ratified Twenty-second Amendment, Truman did not run again in the 1952 election because of his low popularity. He was succeeded by Republican Dwight D. Eisenhower who had attacked Truman's 
Title: Timeline of the Harry S. Truman presidency
Content:  The presidency of Harry S. Truman began on April 12, 1945, when Harry S. Truman became the 33rd president upon the death of Franklin D. Roosevelt, and ended on January 20, 1953.
Title: Harry S. Truman
Content:  Harry S. Truman (May 8, 1884 – December 26, 1972) was the 33rd president of the United States, serving from 1945 to 1953. A lifetime member of the Democratic Party, he previously served as the 34th vice president from January to April 1945 under Franklin Roosevelt, and as a United States Senator from Missouri from 1935 to January 1945. Having assumed the presidency after Roosevelt's death, Truman implemented the Marshall Plan to rebuild the economy of Western Europe and established both the Truman Doctrine and NATO to contain the expansion of communism. He proposed numerous liberal domestic reforms, but few were enacted by the Conservative Coalition that dominated the Congress. Truman grew 
Title: Harry S. Truman 1948 presidential campaign
Content:  the vice-presidential nominee. The Roosevelt–Truman ticket won the presidential election, defeating the Republican ticket of Thomas E. Dewey and John W. Bricker. Truman was sworn in as vice president on January 20, 1945. He had been vice president for 82 days when Roosevelt died on April 12, 1945, making Truman the 33rd president. Explaining the burden of the presidency, Truman said: "I felt like the moon, the stars, and all the planets had fallen on me." Truman asked Roosevelt's cabinet members to remain in their positions, telling them he was open to their advice. He emphasized a central principle of his administration: he 
Title: History of the United States (1945–1964)
Content:  Truman, a self-educated farm boy from Missouri, stood in sharp contrast to the urbane and imperious Roosevelt who kept personal control of all major decisions. Truman was a folksy, unassuming president who relied on his cabinet, remarking "The buck stops here" and "If you can't stand the heat, you better get out of the kitchen." He replaced nearly all of Roosevelt's cabinet, often with old friends from his Senate days. Truman faced many challenges in domestic affairs. His poll ratings were sky high when he took office in April 1945 after Roosevelt's sudden death, then plunged to low levels for most of his eight years in office. The disorderly postwar reconversion of 
Title: Timeline of the Harry S. Truman presidency
Content: April 12 – Harry S. Truman is inaugurated as the 33rd president of the United States in a ceremony in the Cabinet Room, the oath being administered by Chief Justice of the United States Harlan F. Stone and completed exactly two hours and thirty four minutes after the death of Franklin D. Roosevelt. ; April 13 - Several labor unions in official and unofficial capacities pledge support for President Truman. ; April 14 - President Truman attends FDR's funeral. The White House announces President Truman's first press conference of his tenure will be held in three days. ; April 15 - President Truman attends Roosevelt's burial services. ; April 16 - President Truman addresses a joint session of Congress, during 
Title: Harry S. Truman 1948 presidential campaign
Content:  President Truman and Vice President-elect Barkley were inaugurated on January 20, 1949—the first nationally televised inauguration. In his second term as president, Congress ratified the 22nd Amendment, making a president ineligible for election to a third term or for election to a second full term after serving more than two remaining years of a term of a previously elected president. As Truman was eligible to run in 1952, he contested the New Hampshire primaries, but lost to Senator Estes Kefauver. During the Korean War, his approval rating had dropped to approximately 20%. A few days after the New Hampshire primary, Truman formally announced he would not seek 
Title: Relief of Douglas MacArthur
Content:  Harry S. Truman became president of the United States on the death of Franklin D. Roosevelt in 1945, and won an unexpected victory in the 1948 presidential election. He was the only president who served after 1897 without a college degree. Although not highly educated, Truman was well read. When his high school friends went off to the state university in 1901, he enrolled in a local business school, but only lasted a semester. He later took night courses at the Kansas City Law School, but dropped out. Truman attempted to gain admission to the United States Military Academy at West Point, but was rejected for his poor eyesight. He was proud of his military service in the artillery during World War I, and continued to hold a reserve commission, eventually achieving the rank of colonel. Instead 
Title: First inauguration of Harry S. Truman
Content:  The first inauguration of Harry S. Truman as the 33rd president of the United States was held at 7:00 pm on Thursday, April 12, 1945, at the Cabinet Room inside the White House in Washington, D.C., following the death of President Franklin D. Roosevelt earlier that day. The inauguration—the seventh non-scheduled, extraordinary inauguration to ever take place—marked the commencement of the first term (a partial term of 3 years, 284 days) of Harry S. Truman as president. Truman, then serving as Vice President of the United States, had just adjourned a session of the United States Senate and was on his way to share a 

Question: when did truman become president?
Answer: 4/12/1945.