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 clothing, plaid shirts, field jackets and nautical-themed accessories. Vacationing in Palm Beach, Florida, long popular with the East Coast upper class, led to the emergence of bright colour combinations in leisure wear seen in some brands such as Lilly Pulitzer. By the 1980s, other brands such as Lacoste, Izod and Dooney & Bourke became associated with preppy style. Today, these styles continue to be popular on Ivy League campuses, throughout the U.S., and abroad, and are oftentimes labeled as "Classic American style" or "Traditional American style". The Ivy League is often associated with the upper class White Anglo-Saxon Protestant community