2005 NCAA conference realignment
The 2005 NCAA conference realignment was initiated by the movement of three Big East Conference teams (Boston College, University of Miami, and Virginia Tech) to the Atlantic Coast Conference, which set events into motion that created a realignment in college football, as 23 teams changed conferences and Army became an independent. == Affected conferences == === Big East Conference === In 2003 the Big East was put on watch as the ACC announced plans to expand from nine teams to twelve, which under NCAA rules would have enabled them to hold a special conference championship football game.
Source: Wikipedia — 2005 NCAA conference realignment (CC BY-SA 4.0)