The Athletic Base Ball Club of Philadelphia were one of the dominant teams of the area. Philadelphia had been one of the first cities to have baseball games played by local amateurs.

The Athletic Club first gained attention, when Harper's Weekly chronicled a match between Athletic and Atlantic of Brooklyn for the amateur baseball championship in 1866. A famous Harper's illustration shows the Athletic players in uniforms with the familiar blackletter "A" on front.

As newspapers began covering baseball, they were referred to as the Philadelphia Athletics.