(or, ping: LGO
)
Going by the following
page, the minor league classification system went from A (high), B, C, D (low) in 1902 to AA (high), A, B, C, D (low) in 1912.
How did the classifications shift? I know the A leagues (Eastern League, American Assn., PCL) became AA leagues. Some B leagues (Southern Association) shifted, some stayed B, and so on. Was there any rhyme or reason to how this happened? Was Class A just shoved in there? Likewise for 1936 (A1).
I'm trying to put together a good list of historical minor leagues that stuck around for long enough to justify creating a universe with them. The highest classifications are easy... very stable. The ones below that? Ugh.