During the 1960 and 1966 seasons, the league had an odd number of teams due to expansion. Each week during those seasons, one team had a bye, including one team each in the first and last week of the season. (Thus, because they had to play all their games with no break in the middle, those two teams effectively had "no" byes.) The American Football League (at the time a completely separate league, but later became the American Football Conference) also had an odd number of teams in 1966 and 1967 following the addition of the Miami Dolphins, leaving each team with two bye weeks.