Through an error of judgment, a Polish prince allowed a German order of crusaders to settle on the Baltic, to convert the Prussians, Europe's last pagans, to Christianity. But the Teutonic Order quickly turned against Poland, encroaching on its territory. A classic by 19th century novelist Henryk Sienkiewicz tells the story of how Poles fought to control the awkward neighbour. In 1410, the Poles defeated the Teutonic Order in the famous battle of Grunwald.