The horned cap – a cap with up to seven superimposed pairs of horns -was, from the Early Dynastic I Period onwards, the characteristic headdress of deities and heroes.
The origins of the horned cap as a symbol of divinity may derive from the horns of bos primigenius, the wild cattle which flourished throughout the Near East even after the domestication of cattle. Wild cattle certainly remained extant until the Neo-Assyrian period when they were depicted as being hunted by Assyrian rulers. A large species, standing 2 metres tall at the shoulder and endowed with a large pair of sweeping horns, the wild cattle bull must have inspired considerable awe. This power explains the use of the wild bull as a literary and visual metaphor for kings and gods.
The horned cap could be shown worn by a god or man (hero), or simply by itself (often on a stand) as a seperate symbol (this usage particularly prevalent from the late Kassite period, transmitted through the Neo-Babylonian dynasty into Achaemenid Persian art, where it continued as a symbol of divinity). The style of the horned cap changed throughout time – domed or flat-topped, trimmed with feathers or surmounted by a knob or other decorative device.
A general marker of divine or semi-divine status, its employment as the symbol of a specific deity was never set. Kassite kudurrus name the cap as a symbol of the god An; by the Neo-Assyrian period, however, it had come to symbolise the national deity Aššur – three caps together frequently symbolised Aššur, An and Enlil. In Babylonia, two caps symbolised simply An and Enlil, with an occasional third symbolising Ea (Enki) in lieu of his ram-headed staff.