the ground until a fall was made. Irish immigrants later brought this style of wrestling to the United States, where it soon became widespread, especially because of the success of the wrestling champion of the Army of the Potomac, George William Flagg from Vermont. Catch-as-catch can was the style performed by at least a half dozen U.S. presidents, including George Washington, Zachary Taylor, Abraham Lincoln, Andrew Johnson, Ulysses S. Grant, and Theodore Roosevelt. Because of the widespread interest in and esteem of professional Greco-Roman wrestling and its popularity in many international meets in nineteenth century Europe, freestyle wrestling (and wrestling as an amateur sport in general) had a tough time gaining ground on the continent. The 1896 Olympic Games had only one wrestling bout, a heavyweight Greco-Roman match. Freestyle wrestling first emerged as an Olympic sport in the St. Louis Olympics of 1904. All 40 wrestlers who participated in the 1904 Olympics were American. The 1904 Olympics sanctioned the rules commonly used for catch-as-catch-can, but imposed some restrictions on dangerous holds. Wrestling by seven weight classes—47.6 kg (104.9 lb), 52.2 kg (115.1 lb), 56.7 kg (125.0 lb), 61.2 kg (134.9 lb), 65.3 kg (143.9 lb), 71.7 kg (156.7 lb), and greater than —was an important innovation in the Summer Olympics. Since 1921, the body now known as United World Wrestling (UWW), which has its headquarters near Lausanne, Switzerland, has set the "Rules of the Game", with regulations for scoring and procedures that govern tournaments such as the World Games and the competition at the Summer Olympics. These were later adopted by the Amateur Athletic Union (AAU) for its freestyle matches. Freestyle wrestling gained great popularity in the United States after the Civil War. By the 1880s, tournaments drew hundreds of wrestlers. The rise of cities, increased industrialization, and the closing of the frontier provided the affable environment for amateur wrestling, along with boxing, to increase in esteem and popularity. Amateur wrestling teams soon emerged, such as the wrestling team of the New York Athletic Club, which had its first tournament in 1878. Professional wrestling also developed, and by the 1870s, professional championship matches offered allowances of up to $1,000. Nineteenth century wrestling matches were particularly long, and especially Greco-Roman bouts (where holds below the waist and the use of the legs are not allowed) could last as many as eight to nine hours, and even then, it was only decided