The promontory, known in antiquity as the promontory Cosano (from the Etruscan city of Cosa [Cosa or Cosae] that stood on the coast near the detachment of the tomb of Feniglia), is remembered with the current name (Argentarius mons) the first vault in Rutilio Namaziano (Itin., I, 315 ff.); a name not derived certainly from silver mines, which were never there, but, as the santi and the Repetti argue, from the sheen of the micaceous rocks or, as Assunto Mori believes (Boll. Soc. Geogr., 1922, p. , from the office of argentarî or bankers held by the people Domitia, owner of the place, where he practiced the fishing profitably.
