In 1998, a new system was put into place called the Bowl Championship Series. For the first time, it included all major conferences (ACC, Big East, Big 12, Big Ten, Pac-10, and SEC) and four major bowl games (Rose, Orange, Sugar and Fiesta). The champions of these six conferences, along with two "at-large" selections, were invited to play in the four bowl games. Each year, one of the four bowl games served as a national championship game. Also, a complex system of human polls, computer rankings, and strength of schedule calculations was instituted to rank schools. Based on this ranking system, the No.1 and No.2 teams met each year in the national championship game. Traditional tie-ins were maintained for schools and bowls not part of the national championship. For example, in years when not a part of the national championship, the Rose Bowl still hosted the Big Ten and Pac-10 champions.