The classical scholar Miryam Librán-Moreno writes that Tolkien drew heavily on the general history of the Goths, Langobards and the Byzantine Empire, and their mutual struggle. Historical names from these peoples were used in drafts or the final concept of the internal history of Gondor, such as Vidumavi, wife of king Valacar (in Gothic). The Byzantine Empire and Gondor were both, in Librán-Moreno's view, only echoes of older states (the Roman Empire and the unified kingdom of Elendil), yet each proved to be stronger than their sister-kingdoms (the Western Roman Empire and Arnor, respectively). Both realms were threatened by powerful eastern and southern enemies: the Byzantines by the Persians and the Muslim armies of the Arabs and the Turks, as well as the Langobards and Goths; Gondor by the Easterlings, the Haradrim, and the hordes of Sauron. Both realms were in decline at the time of a final, all-out siege from the East; however, Minas Tirith survived the siege whereas Constantinople did not. In a 1951 letter, Tolkien himself wrote about "the Byzantine City of Minas Tirith."