Plutarch, Numa
Bernadotte Perrin, Ed.

[5] But the dance is chiefly a matter of step; for they move gracefully, and execute with vigour and agility certain shifting convolutions, in quick and oft-recurring rhythm.

The bucklers themselves are called ‘ancilia,’ from their shape; for this is not round, nor yet completely oval, like that of the regular shield, but has a curving indentation, the arms of which are bent back and united with each other at top and bottom this makes the shape ‘ancylon,’ the Greek for curved. Or, they are named from the elbow on which they are carried, which, in Greek, is ‘ankon.’ This is what Juba says, who is bent on deriving the name from the Greek. But the name may come from the Greek ‘anekathen,’ inasmuch as the original shield fell from on high; or from ‘akesis,’ because it healed those who were sick of the plague; or from ‘auchmon lysis,’ because it put an end to the drought; or, further, from ‘anaschesis,’ because it brought a cessation of calamities, just as Castor and Pollux were called Anakes by the Athenians; if, that is, we are bound to derive the name from the Greek.