Complex sentence: The 1998 Minnesota Vikings became only the third team in NFL history to win 15 games during the regular season joining the 1984 San Francisco 49ers and the 1985 Chicago Bears.
Split into simpler sentences: The 1998 Minnesota Vikings became only the third team in NFL history to win 15 games during the regular season. The first two were the 1984 San Francisco 49ers and the 1985 Chicago Bears.