The origin of professional football can be traced back to 1892, with William "Pudge" Heffelfinger's $500 contract to play in a game for the Allegheny Athletic Association against the Pittsburgh Athletic Club grew as it became the dominant version of the sport in the United States for the first half of the 20th century In the late 19th and early 20th centuries, gameplay developments by college coaches such as Eddie Cochems, Amos Alonzo Stagg, Parke H. Davis, Knute Rockne, and Glenn "Pop" Warner helped take advantage of the newly introduced forward pass football played in Britain in the mid–19th century, in which a football is kicked at a goal or kicked over a line, which in turn were based on the varieties of English public school football games.