The Copa Libertadores is a seasonal association football competition that was established in 1960. It begins in mid-January and ends with the final in November of the same year. The Copa Libertadores is open to the league champions of CONMEBOL member associations; clubs finishing from second to fourth position in the stronger leagues of the region, such as the Brazilian league, are also included. Originally, only the champions of their respective national league could participate in the competition. However, in 1966 this was changed to allow the runners-up of the leagues to compete. Until 2018, the final was contested over two legs, one at each participating club's stadium. From 2019, the format was changed, with the final being a single game played at a predetermined venue.