In the Second Polish Republic, there was not a national, Second Division, as we know it today, although the creation of the second division was proposed on several occasions. On Sunday, 26 September 1937 in Częstochowa, a conference of regional teams from across the nation took place, to discuss the creation of the league. Officials of several clubs arrived, such as Brygada Częstochowa, Gryf Toruń, Śmigły Wilno, Rewera Stanisławów, Dąb Katowice, Unia Sosnowiec, Strzelec Janowa Dolina, and WKS Grodno. Also, invited were officials of HCP Poznań, Podgorze Kraków, Naprzód Lipiny and Union Touring Łódź, but for unknown reasons they did not show up. The officials talked about creation of a National B-League, but nothing came out of this project. Instead, in the years 1921-1939, several Voivodeships held their own games and those leagues were known as A-Classes. In 1927, the elite Polish Football League was created, which by the late 1930s consisted of 10 teams. The teams that did not make it to the Ekstraklasa, played in the A-Classes.

I liga, currently named Fortuna I liga due to its sponsorship by Fortuna, is the men's second professional association football division of the Polish football league system, below the Ekstraklasa and above the II liga via promotion/relegation systems. Run by the Polish Football Association (PZPN) since its inception on 30 May 1948. The league was renamed from Second League to First League in 2008. It is currently contested by 18 teams, from 2002 all clubs onwards must have a licence, issued by the Association.