The AL and NL also employed and trained their own umpires, who only worked regular season games in their own league.

However, with the advent of free agency in the 1970s allowing for more player movement between leagues, the introduction of regular season interleague play in 1997, umpires working games across MLB beginning in 1999, and the NL's adoption of the designated hitter rule in 2022, the difference in play between the two major leagues has diminished considerably.

Though both leagues agreed to be jointly governed by a commissioner in 1920, they remained separate business entities with their own presidents and management.

A historical marker is at the intersection of North Dr. Martin Luther King Jr. Drive and West Kilbourn Avenue where the hotel once stood.

[2] Babe Ruth, noted as one of the most prolific hitters in Major League Baseball history, spent the majority of his career in the American League with the Boston Red Sox and the New York Yankees.

Until the late 1970s, league umpires working behind home plate wore large, balloon-style chest protectors worn outside the shirt or coat, while their colleagues in the National League wore chest protectors inside the shirt or coat.

Most umpires made the switch to the inside protector, led by Don Denkinger in 1975 and Jim Evans the next year, although several did not, including Bill Haller, Russ Goetz, George Maloney, Bill Kunkel and Jerry Neudecker, who became the last full-time MLB umpire to use the outside protector in 1985.

The initial plan was to have three five-team divisions per league with inter-league play year-round—possibly as many as 30 interleague games per team each year.

Beginning in 1997, interleague games have been played during the regular season and count in the standings.

Those eight franchises constituted the league for 52 seasons until the Browns moved to Baltimore and took up the Orioles name.

Due to the 1994–95 Major League Baseball strike, there were no pennant or World Series winners in 1994, so this year is left blank.