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 sixteen men's and sixteen women's sports. In some sports, Ivy teams actually compete as members of another league, the Ivy championship being decided by isolating the members' records in play against each other; for example, the six league members who participate in ice hockey do so as members of ECAC Hockey, but an Ivy champion is extrapolated each year. In one sport, rowing, the Ivies recognize team champions for each sex in both heavyweight and lightweight divisions. While the Intercollegiate Rowing Association governs all four sex- and bodyweight-based divisions of rowing, the only one that is sanctioned by the NCAA