Pac-10, about to become Pac-12, can trace roots to 1916 football season.

Dec. 2, 1915

The Pacific Coast Conference is formed at a meeting in a Portland hotel. Charter members are Washington, Oregon, Oregon Agricultural College (now Oregon State) and California. The conference begins play in 1916.

1917

Washington State joins.

1918

Stanford joins.

1922

USC and Idaho join.

1924

Montana joins.

1928

UCLA joins, making it a 10-school conference.

1950

Montana leaves the conference, which continues with nine schools though the 1958 season.

1959

After several pay-for-play scandals, most notably at Washington and UCLA, the PCC disbanded. Washington and the four California schools first attempted to form a super conference with Army, Navy, Air Force, Notre Dame, Duke and Penn State, among others. But that didn’t work out and the five former PCC schools reformed as the Athletic Association of Western Universities, not allowing Oregon, Oregon State or Washington State to join. Idaho, which hadn’t won a conference game the previous four seasons, did not seek entrance to the AAWU. The conference was known informally as the Big Five.

1962

Washington State joins the conference now known as the Big Six.

1964

Oregon and Oregon State join, and the conference is known as the Pacific-8 (name change became official in 1968), continuing play with eight teams through 1977.

1978

Arizona and Arizona State join, creating the Pacific-10. The conference remains unchanged for 33 seasons.

2011

Utah and Colorado will begin play in the Pacific-12 Conference.