The double-headed eagle was first seen in Mesopotamia, at the end of 3.000 and beginning of 2000 B.C. Then it overspread to Central Asia and Anatolia, where it was used by Turk civilizations with a good grace.
The two-headed eagle can be found in the archaeological remains of the Sumerian civilization and through the Hittite civilization, dating from a period that ranges from the 20th century BC to the 7th century BC. From there it passed to the empires Akkadian, Assyrian, Sasani and Byzantine. At the same time the motive was used in the big Hittite Kingdom, in Hattusa, Alacahöyük and Yazılıkaya.
In Shamanism, Central Asia, the eagle is the guard of the door of steel between the human and the spirit world. Humans are accompanied by birds in their journeys on earth and in heaven. The eagle is the most empyreal one among the birds.
The double-headed eagle was first seen in Mesopotamia, at the end of 3.000 and beginning of 2000 B.C. Then it overspread to Central Asia and Anatolia, where it was used by Turk civilizations with a good grace.
The motive was also used in the Byzantine Empire, as a symbol of the unity of the government and the church. Starting in the 14th century, the double-headed eagle took also place in the emblem of the sacred Roman Empire’s dynasties. Later it was a symbol of nobility in Europe. The eagle was also used in the emblems of the German, Austria-Hungary and Russian empires.
Even if it is stated, that the motive was first seen in Central Asia, it is interesting to see, that it was used in Anatolia, before the Turks settled down. The double-headed eagle is the symbol of exaltation and ascendance, that’s for sure. But there is no consensus of opinion about its origin.
Since 1970 the municipality of Konya, capital of Seljuk Civilization, uses the double-headed eagle as its symbol.
(Source: http://www.tarihinizinde.com)