Ivy League Group Agreement to all intercollegiate sports, effective with the 1955–56 basketball season. This is generally reckoned as the formal formation of the Ivy League. As part of the transition, Brown, the only Ivy that hadn't joined the EIBL, did so for the 1954–55 season. A year later, the Ivy League absorbed the EIBL. The Ivy League claims the EIBL's history as its own. Through the EIBL, it is the oldest basketball conference in Division I. As late as the 1960s many of the Ivy League universities' undergraduate programs remained open only to men, with Cornell the only one to have
Ivy League in 1937. Yale and Columbia previously fielded teams in the league but no longer do so. The Ivy League is home to some of the oldest college rugby teams in the United States. Although these teams are not "varsity" sports, they compete annually in the Ivy Rugby Conference. The table above includes the number of team championships won from the beginning of official Ivy League competition (1956–57 academic year) through 2016-17. Princeton and Harvard have on occasion won ten or more Ivy League titles in a year, an achievement accomplished 10 times by Harvard and 24 times by Princeton, including