Known in Akkadian as uškaru, the recumbent crescent moon appears as a common motif within Mesopotamian art from the earliest times. From the Old Babylonian Period at the latest, the crescent moon functioned as the symbol of the moon god Sin / Nanna-Suen. Although seen earlier, from the Kassite era especially, the crescent moon appears within a disc, occasionally appearing as a combination of crescent and solar disc, perhaps symbolising an eclipse. Later, in first millennium contexts (Neo-Assyrian and Neo-Babylonian art), the torso and head of the god Sin is frequently depicted emerging from the crescent. This depiction led, in at least one instance on a Neo-Assyrian cylinder seal, to a complex crescent-based emulation of the winged disc motif, smaller inward-facing deities being positioned on the horns and wings of the moon and arranged around the central moon deity wearing a crescent-headed cap.
Ritually, the crescent moon emblem was often placed on a pole with elaborate trimmings – it could appear as a discreet motif or depicteda s being held by various figures. It seems likely that such an arrangement was believed to hold magically protective powers.