What is the relationship between Teutonic knights and Prussia?

1095, the holy see launched a crusade. After the Crusade began, many knights appeared, that is, militarized friars' organizations. All members must abide by the oath of "poverty, chastity and obedience", can't have private property, can't get married, and absolutely obey the orders of superiors with nosebleeds. Among these knights, the famous ones are the Knights of the Hospital, the Knights Templar and the Teutonic Knights. Compared with the other two, the Teutonic Order seems less famous, but it has a far-reaching impact on history.

Teutonic knights were founded in the Third Crusade. 1 189, Emperor Frederick I of the Holy Roman Empire participated in the Third Crusade, but unfortunately drowned during the March. Many German knights who accompanied him at that time were founded in Palestine because they obtained some fiefs 1 189. The coat of arms is black and white, and the members wear white coats.

Teutonic knights were founded in the Third Crusade. 1 189, Emperor Frederick I of the Holy Roman Empire participated in the Third Crusade, but unfortunately drowned during the March. Many German knights who accompanied him at that time were founded in Palestine because they obtained some fiefs 1 189. The coat of arms is black and white, and the members wear white coats.

Later, in order to legalize the fortress, the leader of the Teutonic Order at that time took advantage of his good relationship with the Holy Roman Emperor (Frederick II at that time) and obtained Prussia as a fief through a paper of letters in 1226.

1234, Pope Gregory IX issued another imperial edict, announcing that all fiefs and occupied lands of Prussia knights in the future would be under the protection of the Pope as their permanent property. At this point, it was further legalized. By 1283, the Teutonic Order not only conquered the Prussians, but also converted them to Christianity, and attracted more immigrants from Germany, and finally established the Teutonic Order State here.