as having displayed an eagle on his banner, Otto IV ( 1209–15) an eagle hovering over a dragon. The first evidence of the use of the Reichsadler (imperial eagle) proper dates to the mid-13th century. Matthew Paris' Chronica Majora (c. 1250) displays a coat of arms with a black double-headed eagle in a yellow field for Otto IV. Segar's Roll (c. 1280) displays the same coat of arms, or, an eagle sable beaked and armed gules for the "king of Germany" (rey de almayne). Outside of these exceptional depictions (in sources from outside of Germany), the double-headed eagle remains unattested as emblem of the German kings or emperors until the 1430s. In the 14th century, the German kings use the royal banner (Königsfahne) with the single-headed eagle. The earliest pictorial representations of this date to the first half of the 14th century (Codex Balduini). This banner develops into the Reichssturmfahne (imperial war flag) with the double-headed Reichsadler (imperial eagle) by the mid-15th century. Sigismund (r. 1433–37) still uses either the single-headed or the double-headed eagle. Consistent use of the double-headed eagle only begins with the Habsburg emperors (with Frederick III, 1440). After 1558 (Ferdinand I), the title of King of the Romans is used for the emperor's heir apparent; the double-headed eagle now represents the emperor, and the single-headed eagle the emperor's heir apparent (thus, Ferdinand IV, King of the Romans, who pre-deceased his father in 1654 and never became emperor, is given a single-headed eagle only). Byzantine imperial eagle Use of the double-headed eagle is first attested in Byzantine art of the 10th century. Its use as an imperial emblem, however, is considerably younger, attested with certainty only in the 15th century, i.e. at about the same time the double-headed eagle was also adopted in the Holy Roman Empire. There are speculative theories according to which the double-headed eagle was first introduced as a dynastic emblem of the Komnenoi, from as early as the 11th century. The Palaiologoi emperors appear to have used the double-headed eagle often as ornamental emblem on their robes etc. during the 13th and 14th century, but only in the 15th century as an emblem on coins or seals. In the 15th century, the double-heade eagle was first used as an emblem by the semi-autonomous Despots of the Morea, who were younger imperial princes, and by the Gattilusi of Lesbos, who were Palaiologan relatives and