Before 1945
After Poland regained independence with the end of the World War I in 1918, the party merged with agrarian groups from territories previously occupied by Imperial Russia and formed the first PSL led by Wincenty Witos, becoming one of the most important political parties in the Second Polish Republic until it was removed by the Sanacja regime (see also People's Party).
During this time there were two parties using the term "Polish People's Party": Polish People's Party "Piast" and Polish People's Party "Wyzwolenie". During World War II, PSL took part in forming the Polish government in exile.
Read more about this topic: Polish People's Party, History