The NSL was organized as a minor league by Thomas T. Wilson in 1920 and lasted until 1936. It is considered a major league only for the 1932 season. Prior to the season, several established teams joined the NSL, mainly from the collapsed Negro National League. it was also the only organized league to finish its full schedule in 1932 (primarily due to the Great Depression).
I sincerely appreciate the research work, and the information being shared. It is important and interesting history.