Double-headed eagle emblem of the Byzantine Empire. The head on the left (West) symbolizes Rome, the head on the right (East) symbolizes Constantinople. The cross and orb in the claws symbolize, respectively, spiritual and secular authority.

The double-headed eagle is a common symbol in heraldry and vexillology. It is most commonly associated with the Byzantine Empire. In Byzantine heraldry, the heads represent the dual sovereignty of the Emperor (secular and religious) and/or dominance of the Byzantine Emperors over both East and West. Several Eastern European nations adopted it from the Byzantines and continue to use it as their national symbol to this day, the most prominent being Russia. However, the design was in use in the East for centuries before it was officially adopted by the Byzantines, and was independently adopted as the symbol of several other historical states, such as early medieval Armenia and possibly the Seljuk Sultanate of Rûm.

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