Teutonic knights were not conected with ancient Teutons. They were knight order (like Templars or Hospitaliers). the only conection is fact that candidates for Teutonic knights had to be ethnicaly German.

Order was created in Palestine in 1198, but quickly moved to Europe. In 1225 they were granted land by Polish prince Konrad Mazowiecki (of Mazovia) who wanted them to fight Prus tribes attacking his land. In 1230 they get Pope's protection which allowed them to be independent. In about 50 years (to 1283) captured whole Prus lands. From this point they concentrated on fighting against Lithuania and Poland.

In 1525 became protestant vasal to Polish King and in 1667 independent kingdom called Prussia.