The Campeonato Paulista Série A1, commonly known as Campeonato Paulista, nicknamed Paulistão, is the top-flight professional football league in the Brazilian state of São Paulo. Run by the FPF, the league is contested between 16 clubs and typically lasts from January to April. Rivalries amongst four of the best-known Brazilian teams (Corinthians, Palmeiras, Santos and São Paulo) have marked the history of the competition. The Campeonato Paulista is the oldest established league in Brazil, being held since 1902 and professionally since 1933. Format Campeonato Paulista is held annually by the Federação Paulista de Futebol (São Paulo State Football Federation), or FPF, amongst teams residing within the state of São Paulo. 20 clubs compete in the highest level of the championship (Série A1). In a new format starting in 2007, each team plays the others once in a round-robin format, followed by a four-team playoff with home-and-away series. In addition, teams that finish the regular season in places 5 through 8 (that do not reside within the city of São Paulo or Santos) will compete in a playoff for the title of "Campeão do Interior" (Upstate Champion). The four lowest placed teams are relegated to the lower competition (Série A2) for the following year. Série A2 is contested by 20 teams in three separate phases. In Phase One, the teams are split into two groups, playing each other twice in a home-and-home series. The bottom two from each group are relegated to Série A3; the top four advance to Phase Two. Phase two consists of the eight advancing teams organized into groups, repeating the home-and-home series within the group. The top two placed teams from each group are promoted to Série A1; each top team advances to Phase Three, a single championship game to determine the tournament winner. Série A3 consists of 20 teams competing in a three phase format similar to Série A2. Promotion and relegation rules are the same as in this higher level. The Second Division (Série B) matches are held by minor teams during the Brazilian league. The number of teams involved varies, with 45 participants in 2011. Top four teams are promoted to Série A3. History Founding Charles Miller was responsible for the creation of the first São Paulo state tournament. Miller introduced the football association rules to Brazil upon his return from England, where he attended college and discovered the sport. On December 14, 1901,