A commercial and defensive federation of merchant guilds based in harbour towns along the North Sea and Baltic coasts, the Hanseatic League eventually dominated maritime trade in Northern Europe and spread its influence much further afield.

The League was formed to protect the economic and political interests of member cities throughout a vast and complex trading network. During its 300 years of dominance the League's large ships – called 'cogs' – were at the forefront of maritime technology, were early users of cannon, and were manned by strong fighting crews to defend them from pirates in both open-sea and river warfare. David Nicolle explores these approaches, as well as the fortifications and gunpowder weapons they invested in, to protect them from the sieges they were subjected to.

Featuring specially commissioned artwork, this is first detailed, illustrated study in English of the fighting men, weapons and ships of the greatest mercantile and naval power of medieval northern Europe.