Theodore Roosevelt Jr., often referred to as Teddy or his initials T. R., was an American statesman, conservationist, naturalist, historian, and writer, who served as the 26th president of the United States from 1901 to 1909. Theodore Roosevelt unexpectedly became the 26th president of the United States in September 1901 after the assassination of William McKinley.

William Howard Taft was the 27th president of the United States and the tenth Chief Justice of the United States, the only person to have held both offices. Taft was elected president in 1908, the chosen successor of Theodore Roosevelt.

Thomas Woodrow Wilson was an American politician and academic who served as the 28th president of the United States from 1913 to 1921. A member of the Democratic Party, Wilson served as the president of Princeton University and as the 34th governor of New Jersey before winning the 1912 presidential election.

Warren Gamaliel Harding was the 29th president of the United States, serving from March 4, 1921 until his death in 1923. A member of the Republican Party, he was one of the most popular U.S. presidents to that point.

Calvin Coolidge was an American politician and lawyer who served as the 30th president of the United States from 1923 to 1929. A Republican lawyer from New England, born in Vermont, Coolidge worked his way up the ladder of Massachusetts state politics, eventually becoming governor of Massachusetts.