The double-headed eagle is a common symbol in heraldry and vexillology. It is most commonly associated with the Byzantine Empire, the Holy Roman Empire, the Russian Empire and their successor states. In Byzantine heraldry, the heads represent the dual sovereignty of the Emperor without Empress for total control and power both (secular and religious) and/or dominance of the Byzantine Emperors over both East and West. In the Holy Roman Empire’s heraldry, it represented the church and the state.
Francis II (House of Habsburg-Lothringen), the last Holy Roman Emperor (also called Roman German Emperor), resigned in 1806 because of Napoleon’s war (who had founded the French Empire) and the Old Empire ended (founded 800 by Charles I), but Francis had already founded the “Austrian Empire” (as Francis I), in order to continue his government. All the territories which were governed by the House of Habsburg-Lothringen were part of this 2nd Empire (1804-1918), even if these territories belonged already to the Holy Roman Empire during the time of the existence of the Old Empire (both empires co-existed in the years 1804-1806). Francis continued to use the double-headed eagle for his 2nd Empire, and it was called the “Secret Roman Empire”. He got three successors. Francis Joseph I (1848-1916) used the imperial veto against the masonic Cardinal Rampolla in the Papal Election in 1903 (announced in the conclave by the Cardinal of Cracow [at that time Austrian Poland]), and the Conclave elected St. Pius X. His last successor was Blessed Charles I (1916-1918) who lost the Empire after the surrender in World War I.
In addition, the eagle is used in heraldry as a charge, as a supporter, and as a crest. Sometimes just the headless body (“sans head” eagle) or the head replaced with another symbol, as well as parts of the eagle, such as its head, wing or leg, are used as a charge or crest.
The eagle with its keen eyes symbolized perspicacity, courage, strength and immortality, but is also considered “king of the skies” and messenger. With these attributed qualities the eagle became a symbol of power and strength in Ancient Rome.
In Christian symbolism the four living creatures of scripture (a man, an ox, a lion, and an eagle) have traditionally been associated with the Four Evangelists. The eagle is the symbol of Saint John the Evangelist.
In medieval and modern heraldry eagles are often said to indicate that the armiger (person bearing the arms) was courageous, a man of action and judicious. Where an eagle’s wings were spread (“displayed”) it was said to indicate the bearer’s role as a protector.
The depiction of the heraldic eagle is subject to a great range of variation in style. The eagle was far more common in continental European—particularly German—than English heraldry, and it most frequently appears Sable (colored black) with its beak and claws Or (colored gold or yellow). It is often depicted membered (having limbs of a different color than the body) / armed (an animal depicted with its natural weapons of a different color than the body) and langued (depicted having a tongue of a different color than the body) gules (colored red), that is, with red claws / talons and tongue. In its relatively few instances in Gallo-British heraldry, the outermost feathers are typically longer and point upward.
The informal term “spread eagle” is derived from a heraldic depiction of an eagle displayed (i.e. upright with both wings, both legs, and tailfeathers all outstretched). The wings are usually depicted “expanded” or “elevated” (i.e., with the points upward); displayed inverted is when the wings are depicted points downward. According to Hugh Clark, An Introduction to Heraldry, the term spread eagle refers to “an eagle with two heads, displayed,” but this distinction has apparently been lost in modern usage. Most of the eagles used as emblems of various monarchs and states are displayed, including those on the coats of arms of Germany, Poland, and Romania and the United States.
Charlemagne, a Frankish ruler and the first Holy Roman Emperor, died in 814, centuries before the introduction of heraldry. In later periods, a coat of arms attributed to Charlemagne shows half of the body of a single-head black eagle as the symbol of the German emperors next to a fleur-de-lis as the symbol of the kings of France on an impaled shield.
According to Carl-Alexander von Volborth the first instance of the use of an eagle as an heraldic charge is the Great Seal of the Margrave Leopold IV of Austria in 1136, which depicts him carrying a shield charged with an eagle. Also from about this time is a coin showing a single-headed eagle, minted in Maastricht (the Netherlands), dating from between 1172 and 1190 after contacts with the East via the Crusades. One Gilbert d’Aquila was granted Baronetcy of Pevensey by William after the Battle of Hastings. The family who held Pevensey castle and the newly formed Borough of Pevensey used the eagle symbol in the 11th century.
From the reign of Frederick Barbarossa in 1155 the single-headed eagle became a symbol of the Holy Roman Empire. The eagle was clearly derived from the Roman eagle and continues to be important in the heraldry of those areas once within the Holy Roman Empire. Within Germany the placement of one’s arms in front of an eagle was indicative of princely rank under the Holy Roman Empire. The first mention of a double-headed eagle in the West dates from 1250 in a roll of arms of Matthew Paris for Emperor Frederick II.