American football resulted from several major divergences from association football and rugby football, most notably the rule changes were instituted by Walter Camp, a Yale University athlete and coach who is considered to be the "Father of American Football". Among these important changes were the introduction of the line of scrimmage, of down-and-distance rules, and of the legalization of forward pass and blocking. 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. The popularity of college football grew as it became the dominant version of the sport in the United States for the first half of the 20th century. Bowl games, a college football tradition, attracted a national audience for college teams. Boosted by fierce rivalries and colorful traditions, college football still holds widespread appeal in the United States.