[nyapbp]

In the late 1940s, 1950s and into the 1960s, sweatshirts with a crest and the name of the group were also popular. These are usually seen in pictures of powderpuff football competitions and the like. i think the dress rules of the day entered into it and as dress rules relaxed, more clothing with letters became available. It may have been tied into the emergence of blue jeans as everyday wear.