The Atlantic Base Ball Club are expected to arrive in this city at half-past 10 this morning by the Chicago and Alton road. In the afternoon, at 3 o'clock, they will play a match with the Union Club.
-Missouri Republican, June 27, 1868
The Atlantic Club of Brooklyn was probably the best baseball club in the United States during the late 1850s and the 1860s. they entered the 1860s with a dominant nine, and as their players got older and the competition got tougher, the Atlantics replaced their veterans with younger and more talented players and maintained their position at the top rank. The Atlantics are often used as a contrast with the first clubs such as the Knickerbockers, and used to illustrate the changes that occurred in baseball as the sport got more competitive and the will to win overcame the gentlemanly behavior that characterized the natal years of the sport.
Charles A. Peverelly, in his Book of American Pastimes (1866), declared that "the Atlantic Base Ball Club, of Brooklyn, was organized August 14, 1855, and from the day of its entrance upon the base ball field it has occupied and filled a front rank position as a crack playing club. Unlike many of its kindred associations, who place a strong nine in the field for one summer, and perhaps a weak body of players for the ensuing season, the Atlantics have always and at all times had a nine from whom any rival club might almost despair of winning any lasting laurels. It is this extraordinary and unvarying success which has gained for them the title of 'Champions.'"
-Base Ball Founders