Theodore "Teddy" Roosevelt ( /ˈroʊzəvɛlt/ roh-zə-velt; October 27, 1858 – January 6, 1919) was the 26th President of the United States (1901–1909). He is noted for his exuberant personality, range of interests and achievements, and his leadership of the Progressive Movement, as well as his "cowboy" persona and robust masculinity. He was a leader of the Republican Party and founder of the short-lived Progressive ("Bull Moose") Party of 1912. Before becoming President, he held offices at the city, state, and federal levels. Roosevelt's achievements as a naturalist, explorer, hunter, author, and soldier are as much a part of his fame as any office he held as a politician.
Born into a wealthy family, Roosevelt was a sickly child who suffered from asthma and stayed at home studying natural history. To compensate for his physical weakness, he embraced a strenuous life. Home-schooled, he became an eager student of nature. He attended Harvard University, where he boxed and developed an interest in naval affairs. In 1881, one year out of Harvard, he was elected to the New York State Assembly as its youngest member. Roosevelt's first historical book, The Naval War of 1812 (1882), established his professional reputation as a serious historian. After a few years of operating a cattle ranch in the Dakotas, Roosevelt returned to New York City and gained fame fighting police corruption. The Spanish–American War broke out while Roosevelt was, effectively, running the Department of the Navy. He promptly resigned and led a small regiment in Cuba known as the Rough Riders, earning a nomination for the Medal of Honor, which was received posthumously on his behalf on January 16, 2001. After the war, he returned to New York and was elected Governor in a close-fought election. Within two years, he was elected Vice President of the United States.
In 1901, President William McKinley was assassinated and Roosevelt became President at the age of 42, taking office at the youngest age of any U.S. President in history. Roosevelt attempted to move the Republican Party toward Progressivism, including trust busting and increased regulation of businesses. Roosevelt coined the phrase "Square Deal" to describe his domestic agenda, emphasizing that the average citizen would get a fair share under his policies. As an outdoorsman and naturalist, he promoted the conservation movement. On the world stage, Roosevelt's policies were characterized by his slogan, "Speak softly and carry a big stick". Roosevelt was the force behind the completion of the Panama Canal, sent the Great White Fleet on a world tour to demonstrate American power, and negotiated an end to the Russo-Japanese War, for which he won the Nobel Peace Prize. Roosevelt was the first American to win the Nobel Prize in any field.