When first playing AOE2, how many didn’t know who the Teutons were, for example ? Then after reading their history file and starting to play the Barbarossa campaign, “medieval Germans of course !”.
Same for every civ that doesn’t have a direct modern equivalent. Looking at the original AOK list, alright for the Franks and Britons you can guess they are the French and British but the Goths ? Byzantines ? Saracens ? Teutons ? If you didn’t already know the basics in History it could have been a bit confusing.