Double Headed Eagle of the K.u.K.

[Bottlestein]

One of the most enduring symbols of Austria-Hungary is the double headed eagle. I had always thought that this was adopted after the union of Austria and Hungary. However, an author says it's a Hapsburg symbol, and was adopted for their "personal" domains after the Holy Roman Empire was absolved. The more I think about it, the more this explanation makes sense: if it was after the union, the symbol would be two eagles rather than a double-headed fantasy eagle.

Anyway, if the double-eagle is Hapsburg: Are there any heraldic symbols in Spain, Belgium, or Germany that have the double-headed eagle because of this? Is it from Lorraine, but got assimilated by the Hapsburgs?

[CJvR]

I thought it was Bysantian in origin, and then taken over by the Tzars and others to nibble a bit of ancient Imperial glory.

[xt828]

IIRC the double-headed eagle was the symbol of the HRE, and was part of the Habsburg arms due to them being the King of the Germans more or less continuously from the early 15th century until the dissolution of the Empire. It was then adopted as an official part of the Habsburg arms, as opposed to being there due to their rank.

The double-headed eagle is associated in Europe with Imperial status due to the Byzantine Empire - it flowed from them to Serbia, Russia and the HRE, and is today associated with both countries and organisations - IIRC the flag of the Greek Orthodox Church is a gold double headed eagle outlined in black on a gold background. Generally speaking, the black eagle on gold is associated with the HRE, while the Russian one has the crest of Muscovy on its chest and the Serbian one is white on red.

If I missed anything it's entirely my own fault, feel free to jump in.

[Zinegata]

I believe it's a HRE symbol as well, heavily associated with the Habsburgs because they held the title of Emperor for so long.

[Sea Skimmer]

I thought it was Bysantian in origin, and then taken over by the Tzars and others to nibble a bit of ancient Imperial glory.

Yeah it was used by the Byzantines first, and adapted and modified by a number of European empire before even the fall of Bizantium. It only makes sense, everyone[i/] uses an eagle so how do we defeat this? Clearly with a super two headed eagle!

[xt828]

Didn't the two heads represent Church and Emperor, originally?

[Narkis]

I read that the heads represented the Emperor's authority over both earthly and spiritual matters. And that the emperor who first used it got the idea from a myth from some part of Asia Minor about a double-headed eagle that could lift a cow with its claws. The locals, including that emperor, called on the beast from protection, or something.

[lord Martiya]

As far I know, the double-headed eagle was first used by Sumeres as the symbol of the god Ninurta, and was used also by other peoples in the region, last of them the Hittites until 7th century BC.
For the Eastern Roman switch from single to double head, however, the prevalent theory is the one referred by Narkis, as emperor Isaac Komnenos was from Paphlagonia, a region where Hittites carving of double-headed eagles in the rocks had given birth to such legend. Seljuk Turks copied the Byzantines for a while, but stopped after mid-13th century, while Slavic countries continued for centuries (and still uses it).
The twin-headed eagle was first used in the Holy Roman Empire by Frederick II in 1250, and would later spread to Germany and be adopted by the Austrian Empire in 1806.