Poland I Liga

In 1913 and 1914, the football championship of Austrian Galicia took place. At that time it was called the A Class Championship, with four top teams of the province (Cracovia, Wisła Kraków, Pogoń Lwów and Czarni Lwów). Since there were many more football teams in Galicia, the B Class Championship was made for them. Also, in 1921, already in the Second Polish Republic, there were two levels: winners of regional A Classes played in the national championship, while winners of the B Classes (Cracovia II, Pogoń Lwów II, AZS Warszawa and Union Łódź) had their own tournament. For financial reasons, this idea was abandoned after one year.

In the Second Polish Republic, there were regional leagues, or A Classes, which were the second level of Polish football system, behind the Ekstraklasa, which was formed in 1927, see Lower Level Football Leagues in Interwar Poland. Since in the late 1930s only two teams were promoted to the Ekstraklasa, and there were as many as fourteen regional champions, there was a complicated system of playoffs. Firstly, winners of neighbouring A Classes played each other, and in the final stage, four teams competed, with two top sides winning the promotion.

Second-level league was first created for the 1949 season, and was split into northern and southern sections, each comprising 10 teams. First plans to create this league appeared in 1947. On 14 and 15 February 1948, a meeting of officials of Polish Football Association took place in Warsaw. Officials from Gdańsk promoted the creation of the league, but this idea was opposed by the delegates from the most powerful regions of Polish football: Kraków, Łódź, Upper Silesia and Warsaw. On 30 May 1948, however, the second division was officially approved, with 18 teams in one group. On 19 February 1949, Polish Football Association decided to expand the league to 20 teams, divided into northern and southern groups.

First games of the new, second division, took place on 20 March 1949, with the first goal scored by Jozef Kokot of Naprzód Lipiny, in a game between Naprzód and Błękitni Kielce. First winners of the second division were Garbarnia Kraków (northern group) and Górnik Radlin (southern group): both sides were promoted to the Ekstraklasa. To determine a winner of the 1949 season of the second division, Górnik had to play Garbarnia in three extra games (4–2, 0–2 and 4–3). The top scorer of the first season was Mieczysław Nowak of Garbarnia, with 24 goals. Relegated were the teams of Ognisko Siedlce and PTC Pabianice (northern group), and Błękitni Kielce and Pafawag Wrocław (southern group).

For the 1951 season, the format was changed to four groups, with eight teams in each group.

For the 1973–74 season, the second level was changed to comprise two sections, split into north and south.

For the 1989–90 season, the league reverted to a single group.

In 2000, the number of teams was limited to 20 sides, then to 18. Champions and runners-up received automatic promotion, while third place teams competed in playoffs. The bottom four teams were relegated.

From the 2008–09 season, the league was renamed as I liga. The number of teams competing remained at 18. Teams placed 15-18 were automatically relegated to II liga (West or East), while the top two finishers were promoted to the Ekstraklasa. In 2014, II liga merged into one group and these rules were changed – the three worst-ranked teams are relegated, and the 15th I liga club compete in playoffs with the fourth placed II liga team. In 2018, the relegation playoff was removed. Since the 2019–20 season, the top two teams are automatically promoted, whilst teams placed 3–6 compete in a playoff for the final third spot.