The Great Eagles ruled by "Thorondor" ["sic"] already appeared in the first tale about Middle-earth that Tolkien wrote in late 1910s, "The Fall of Gondolin", published in "The Book of Lost Tales". The role of Thorondor was expanded in stages, with the successive introduction of the relevant plot elements; and after the conception of Númenor entered in 1930s, the notion that the eagles were the messengers of Manwë was further elaborated. Soon after, Tolkien introduced the eagles into "The Hobbit" and "The Lord of the Rings", repeating in the latter some plot elements and names present in older writings.