vassals. The double-headed eagle was used in the breakaway Empire of Trebizond as well. Western portolans of the 14th–15th centuries use the double-headed eagle (silver/golden on red/vermilion) as the symbol of Trebizond rather than Constantinople. Single-headed eagles are also attested in Trapezuntine coins, and a 1421 source depicts the Trapezuntine flag as yellow with a red single-headed eagle. Apparently, just as in the metropolitan Byzantine state, the use of both motifs, single and double-headed, continued side by side. Other Balkan states followed the Byzantine model as well: chiefly the Serbians, but also the Bulgarians and Albania under George Kastrioti (better known as Skanderbeg), while after 1472 the eagle was adopted by Muscovy, when Ivan III of Russia married Sophia, daughter of Thomas Palaiologos. The Serbian eagle (in the modern coat of arms of Serbia, 1882) is derived from the coat of arms of the Nemanjić dynasty (16th century), in turn derived from the Byzantine imperial eagle. Use of the double-headed eagle for Serbia is among the examples of early representations in Western portolans (Angelino Dulcert 1339). Eagle of Saint John John the Evangelist, the author of the fourth gospel account, is symbolized by an eagle, often with a halo, an animal may have originally been seen as the king of the birds. The eagle is a figure of the sky, and believed by Christian scholars to be able to look straight into the sun. The better known heraldic use of the Eagle of St. John has been the single supporter chosen by Queen Isabella of Castile in her armorial achievement used as heiress and later integrated into the heraldry of the Catholic Monarchs. This election alludes to the queen's great devotion to the evangelist that predated her accession to the throne. There is a magnificent tapestry with the armorial achievement of the Catholic Monarchs in the Throne Room of the Alcazar of Segovia. The Eagle of St. John was placed on side of the shields used as English consort by Catherine of Aragon, daughter of the Catholic Monarchs, Mary I and King Philip as English monarchs. In Spain, Philip bore the Eagle of St John (single or two figures depending versions) in his ornamented armorial achievements until 1668. The Eagle of the Evangelist was recovered as single supporter holding the 1939, 1945 and 1977 official models of the armorial achievement of Spain and it has been removed in 1981 when