 In its finished appearance in the book, the "Unicorn" is a ship of the third rank, a vessel with three-masts and 50 guns, more than 40metres long and 11metres wide.After publication of "The Secret of the Unicorn", Hergé's Dutch publisher Carlsen Verlag gave him an antique model of a 17th-century Danish ship called the "" ("The Unicorn").Until that moment, Hergé had no idea that a ship with that name, complete with unicorn figurehead, had ever actually existed.