The phrase is, recognizably, a nautical metaphor (when their sails are filled with wind, vessels can glide over the sea quickly and effortlessly) and traces its roots back to the Latin world. The expression a gonfie vele, very popular now in colloquial Italian, seems in fact to echo the similar Latin expression pleno velo. A metaphor, this one, employed by the Latin poet Virgil in the Aeneid, the celebrated epic poem that tells the story of a Trojan hero named Aeneas, the son of prince Anchises and the Greek goddess of love and beauty Aphrodite.