The Portuguese Football League, officially known as the Primeira Liga, is the top professional football division in Portugal. Established in 1934, it features 18 teams competing annually for the championship title. The league operates on a promotion and relegation system with the LigaPro, the second tier of Portuguese football. Each season, teams play a total of 34 matches, facing each opponent twice, once at home and once away. The team with the most points at the end of the season is crowned the champion. Notable clubs in the league include SL Benfica, FC Porto, and Sporting CP, which have a rich history and strong fan bases.