American football emerged in the late 19th century as a hybrid of rugby and soccer, officially beginning with the Rutgers vs. Princeton game on November 6, 1869. Walter Camp, considered the "Father of American Football," transformed the sport between 1880 and 1882 by establishing the line of scrimmage, the system of downs, and 11-player teams. Professionalization followed in 1892 when William "Pudge" Heffelfinger became the first player paid to play. The NFL was founded in 1920, later merging with the AFL in 1970 to create the modern league and the Super Bowl.