Edward throughout his life was somewhat of a style icon and breaking with traditions of dress at the time he often liked to wear more relaxed clothes in "sporty" checks. Glen Plaid was a favorite of his and he was so influential, that to the English, Glen Plaid would henceforth be forever known as "Prince Of Wales check".
It is actually popular today in fact with the current Prince of Wales, Prince Charles. The pattern is certainly more relaxed and a little more flamboyant than other traditional cloth patterns but it is a restrained and genteel flamboyance. Perfect for any gentleman or indeed a prince.