"The eagle is used in heraldry as a charge, as a supporter, and as a crest. Heraldic eagles can be found throughout world history like in the Achaemenid Empire or in the contemporary Republic of Indonesia. The European post-classical symbolism of the heraldic eagle is connected with the Roman Empire on one hand (especially in the case of the double-headed eagle), and with Saint John the Evangelist on the other." - (en.wikipedia.org 08.10.2019)
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