Funny story about how the Pirates got their nickname. In the 1870s team nicknames were just the plural of their location. You had the Bostons, the New Yorks, and the Pirates were the Alleghenys, but when the National League was established, teams joined with nicknames and Pittsburgh retained the Alleghenys nickname.

The rules for teams to retain players were in their infancy, and when the A's neglected to protect a talented infielder, the Pirates scooped him and others up quickly, causing one of the teams in 1891 to complain, "That's what a pirate would do." The Pittsburgh team embraced the name as their own though it didn't appear on jerseys for another 20 years.