Theodore Roosevelt Jr. (October 27, 1858 – January 6, 1919), also known as Teddy or T. R., was the 26th president of the United States, serving from 1901 to 1909. Roosevelt previously was involved in New York politics, including serving as the state's 33rd governor for two years. He served as the 25th vice president under President William McKinley for six months in 1901, assuming the presidency after McKinley's assassination. As president, Roosevelt emerged as a leader of the Republican Party and became a driving force for anti-trust and Progressive Era policies.
A sickly child with debilitating asthma, Roosevelt overcame health problems through his strenuous life. He was homeschooled and began a lifelong naturalist avocation before attending Harvard University. His book The Naval War of 1812 established his reputation as a historian and popular writer. Roosevelt became the leader of the reform faction of Republicans in the New York State Legislature. His first wife Alice Hathaway Lee Roosevelt and mother Martha Bulloch Roosevelt died on the same night, devastating him psychologically. He recuperated by buying and operating a cattle ranch in the Dakotas. Roosevelt served as the assistant secretary of the Navy under McKinley, and in 1898 helped plan the successful naval war against Spain. He resigned to help form and lead the Rough Riders, a unit that fought the Spanish Army in Cuba to great publicity. Returning a war hero, Roosevelt was elected New York's governor in 1898. Because the New York state party leadership disliked his ambitious state agenda, they convinced McKinley to choose him as his running mate in the 1900 presidential election. The McKinley–Roosevelt ticket won a landslide victory.