its all to do with ancient heraldry. sovreign countries with kings would most often use a lion as their bestial emmblem , wheras empires use the eagle and that stems from roman times. both hitler and napoleon did try to re-create the ancient roman ways [white power etc] and the word fascism is taken from the roman fascia, which was an axe wrapped in a bunch of logs that symolised romes might and was carried into battle.