The Teutonic Knights are a Roman Catholic military order. It was formed at the end of the 12th century in Acre, Palestine, during the Crusades. The Teutonic Knights are now a clerical order based in Vienna, Austria.
In 1226 Konrad of Masovia brought the Teutonic Knights to fight against Baltic pagan Prussian tribes. They won quickly and, their new country being Prussia, were called Prussians. The knights started to be a danger for the then weak Poland. Finally, the power of the Teutonic Order was crushed in Battle of Tannenberg in 1410.