mantellum

Mantellum, mantelli, n., second declension, and a late word. Classical Latin has no use for it: the Greek-style cloak is a pallium, the Roman citizen's garment a toga, the soldier's a sagum. Mantellum, spelt mantelum as often as not and shadowed by a masculine mantellus and a mantus, is what the later and medieval corpus reaches for, so its presence dates a text as clearly as its spelling does.

It went everywhere afterwards. Italian mantello, Spanish manto, French manteau, and through French into English as mantle and mantelpiece. The figurative sense arrived early too - something held up in front of a thing to hide it, hence a pretext, which is exactly what English still does with "under the mantle of". Do not go looking for it in Cicero.