The German Imperial Eagle originates from a proto-heraldic emblem believed to have been used by Charlemagne, the first Frankish ruler crowned Holy Roman Emperor by the Pope in 800, and derived ultimately from the Aquila or eagle standard, of the Roman army. The Ottonian and Salian emperors had themselves depicted with the Roman "eagle sceptre", and Frederick II depicted the imperial eagle on his coins. Before the mid-13th century, however, the eagle was an imperial symbol in its own right, not yet used as a heraldic charge depicted as part of a coat of arms. An early depiction of a double-headed eagle in a heraldic shield, attributed to Frederick II of Hohenstaufen, is found in the Chronica Majora by Matthew Paris. The Segar's Roll likewise shows the double-headed eagle as the coat of arms of the King of Germany. The eagle also appears in the seals of imperial cities: that of Kaiserswerth in the 13th century, besides Lübeck, Besançon, Cheb, and others. Use of the imperial eagle as part of the imperial coat of arms of a ruling emperor dates to after the end of the interregnum. Sigismund of Luxembourg used a black double-headed eagle after he was crowned Emperor in 1433. From this time, the single-headed Reichsadler represented the title of King of the Romans, and the double-headed one the title of Emperor. Over the following century, Albert II of Germany was the last King-elect of Germany who did not go on to be crowned emperor. After the German Reformation, beginning with Ferdinand I, emperors were no longer crowned by the pope. The Teutonic Order under Hermann von Salza had the privilege to display the Imperial eagle in their coat of arms, granted by Emperor Frederick II. The black eagle was later adopted when the Teutonic State was transformed into the Duchy of Prussia in 1525, and a modified version was used in the arms of Royal Prussia.
Modern use
In 1804, Holy Roman Emperor Francis II established the Austrian Empire from the lands of the Habsburg Monarchy, and adopted the double-headed eagle, aggrandized by an inescutcheon emblem of the House of Habsburg-Lorraine and the Order of the Golden Fleece, as its coat of arms; the Holy Roman Empire was subsequently dissolved in 1806. Since 1919 the coat of arms of Austria has depicted a single-headed eagle. Although not a national symbol in the modern sense, the Reichsadler evoked sentiments of loyalty to the empire. Following the revolutions of 1848 in the German states, the Reichsadler was restored as a symbol of national unity: it became the coat of arms of the short-lived German Empire and subsequently the German Confederation from its restoration in 1850 until its dissolution in 1866. It was once again restored in 1871 when a single-headed eagle with a Prussian inescutcheon became the insignia of the German Empire; the single head was used to represent the so-called Kleindeutschland, i.e. it excluded Austria. After World War I the Weimar Republic under President Friedrich Ebert assumed a plain version of the Reichsadler, which remained in use until 1935. During Nazi rule, a stylised eagle combined with the Nazi Hakenkreuz was made the national emblem by order of Adolf Hitler in 1935. Despite its medieval origin, the term "Reichsadler" in common English understanding is mostly associated with this specific Nazi-era version. The Nazi Party had used a very similar symbol for itself, called the Parteiadler. These two insignia can be distinguished as the Reichsadler looks to its right shoulder whereas the Parteiadler looks to its left shoulder. After World War II the Federal Republic of Germany re-implemented the eagle used by the Weimar Republic by enactment of President Theodor Heuss in 1950.
