The 3 gold lions on red is the traditinoal English coat of arms - William of Normandy's (William the Conquerer) personal badge was 2 lions - it's not strictly speaking a coat of arms at hat stage tho becuse heraldry wasn't invented for another 50 years or so

Geoffrey Plantegnet, Count of Anjou, was knighted by King Henry I in 1127. His shield was adorned with three golden lions and is thought to be the first example of a coat of arms.

Lions weer wel known world wide - there used to be wild lions in Europe althuogh I'm not sure if thye weer known at this time.