Upon the assassination of President William McKinley in September of 1901, Theodore Roosevelt (1858-1919) became the twenty-sixth President of the United States. Roosevelt's presidency (1901-1909) was shaped by a series of progressive reforms at home and aggressive military expansion abroad. Early in his political career, Roosevelt achieved fame by leading the "Rough Riders," a regiment of U.S. Cavalry volunteers, on a charge up San Juan Hill during the Spanish-American War (1898). The Rough Riders' adventures were heavily publicized and inspired a number of dime novel series, including The Young Rough Riders Weekly.