The Hanseatic nef, or northern ship, appeared in the twelfth century, initially in the coastal towns of the North Atlantic, as well as in the North and Baltic Seas. The Nef is a perfect synthesis of northern and southern shipbuilding, laying the technical foundations for future heavy European shipbuilding. The Nef can be seen as a combination of Scandinavian and Latin shipbuilding. The cog, as a rival to the nef, later becomes the favoured ship of the North Sea and is preferred as an armed transport ship or warship. Nefs and cogs were the favoured ships of North and Baltic Sea pirates such as Gödecke Michels and Klaus Störtebecker.