The British never really enjoyed Greco-Roman wrestling in comparison to its less restrictive counterpart, freestyle wrestling, and neither did the Americans, despite the efforts of William Muldoon (a successful New York barroom freestyle wrestler who served in the Franco-Prussian War and learned the style in France) to promote it in the United States after the Civil War. However, on the continent of Europe, the style was highly promoted. Almost all the continental European capital cities hosted international Greco-Roman tournaments in the 19th century, with much prize money given to the place winners. For example, the Czar of Russia paid 500 francs for wrestlers to train and compete in his tournament, with 5,000 francs awarded as a prize to the tournament winner. Greco-Roman wrestling soon became prestigious in continental Europe. It was the first style registered at the modern Olympic Games, beginning in Athens in 1896 with one heavyweight bout, and grew in popularity during the 20th century. It has always been featured in the Olympic Games, except during the Paris Olympic Games in 1900 and the St. Louis Olympic Games of 1904, when freestyle first emerged as an Olympic sport. Perhaps the most well-known of Greco-Roman wrestlers in the 19th century was Georg Hackenschmidt born in Dorpat, Russian Empire, and nicknamed "The Russian Lion". Hackenschmidt in 1898 at the age of 21 and with 15 months of training defeated the experienced Paul Pons in a match in Saint Petersburg, Russia. In 1900, he won professional tournaments in Moscow and St. Petersburg and a series of international tournaments after that. After defeating Tom Jenkins (from the United States) in both freestyle and Greco-Roman matches in England, Georg Hackenschmidt wrestled exclusively freestyle in order to compete better against English, Australian, and American opponents. Winning more than 2,000 victories in Greco-Roman and freestyle, Hackenschmidt served as the physical education adviser to the House of Lords after his retirement. Professional matches in Greco-Roman wrestling were known for their great brutality. Body slams, choke-holds, and head-butting was allowed, and even caustic substances were used to weaken the opponent. By the end of the 19th century, gouging with the nails, punching, and violently slamming the arms together around the opponent's stomach were forbidden. Greco-Roman matches were also famous for their length. Professionally, it was not uncommon for there to be matches lasting two or three hours. William Muldoon's bout with Clarence Whistler at the Terrace Garden