The Philadelphia Athletics were one of the charter members of the American League when the league debuted for the 1901 season. Their name was based off of a previous ball club from Philadelphia who were named after the athletic club the ballplayers were a mamber of.
After hearing of the new Philadelphia franchise, the second in the city, New York Giants Manager John McGraw told local reporters that new A's owner Benjamin Shibe had a "white elephant" of a team on his hands. A "white elephant" being a phrase used to describe something who's cost is far greater than it's value. In defiance, A's manager Connie Mack insisted on the club adopting a white elephant as their official team mascot which they immediately did. When the Giants and A's faced off in the 1905 World Series, Mack presented McGraw with a stuffed white elephant toy. The A's finally added the elephant to their jerseys in 1918 where it stayed until 1927. Despite it being removed from the jersey the club still used it as a major part of their branding and on publications even up to this day, over 100 years and two relocations later.
The A's were primarily royal blue during their time in Philadelphia, they used a darker shade of blue from 1902-1919 and again for their final 4 seasons, the team also very momentarily switched to a black and white colour scheme for 4 seasons in the mid-1920s. In 1954, after other AL owners voted against a local Philadelphia owner, the club was sold to Chicago businessman Arnold Johnson who promptly moved the team to Kansas City where they became the Kansas City Athletics in 1955.