The Hansekogge (Hanseatic cog) type of ship with its bulbous hull and large hold came into existence in the Middle Ages as a result of the continually growing traffic in goods. The cogs built since the 12th century took longer to build and cost more than previous merchant ships and the high payload was appropriate to the growing volume of trade. This highly seaworthy merchant vessel, the first to bring economic success to the Hanseatic League, was the most important type of ship from the late Middle Ages to the beginning of the 15th century.