How is a Neapolitan mandolin built?

A Neapolitan mandolin by Antonio Vinaccia, made in Naples in 1772 and now at the V&A, shows the classic build. Its rounded body is made of 21 fluted maple ribs, and the belly bends inwards at the level of the bridge. The neck carries 10 silver frets, and eight rear pegs hold four double courses of wire strings: two steel, one brass and one overspun.