The Winged Helmet or Harpa (Go."Gwasgon") originated with the elves and was worn by Noldorin Warriors, especially the fighters of the House of the Wing in Gondolin. Later it was adopted by the Edain and their Numenorean descendants. Late derivations of the winged helmet were still worn by the Gondorians, especially the Guard of the Citadel of Minas Tirith.
Speculations[]
late gondorian Helmets
Various Types of Winged Helmet designs
Tolkien´s description of the winged helmets of the Gondorians and elves seems to match his sketch of the crown of Gondor, shown by him as being based on a tall helmet with wings attached.Tolkien was inspired by Egyptian crowns such as the Hedjet, but maybe also by historical helmets as the Winged Phrygian Helmet, the Assyrian helmet, the conical la téne helmet and the European bronze-age pointed helmet.
His gondorian crown design only shows very small raven-wings attached to the helmets sides, an earlier illustration by JRRT, depicting a dragonslayer, shows a more simple, lower and round helmet type with cheek-guards and very long, possibly swan- or eagle- ,wings.