The State of the Teutonic Order (German: Staat des Deutschen Ordens; Latin: Civitas Ordinis Theutonici), also called Deutschordensstaat or Ordensstaat, was a crusader state formed by the Teutonic Knights or Teutonic Order during the 13th century Northern Crusades along the Baltic Sea. The state was based in Prussia after the Order's conquest of the Pagan Old Prussians which began in 1230. It expanded to include at various times Courland, Gotland, Livonia, Neumark, Pomerelia and Samogitia. Its territory was in the modern countries of Estonia, Latvia, Lithuania, Poland, and Russia. Most of the territory was conquered by military orders, after which German colonization occurred to varying effect.
The Livonian Brothers of the Sword controlling Terra Mariana were incorporated into the Teutonic Order as its autonomous branch Livonian Order in 1237. In 1346, the Duchy of Estonia was sold by the King of Denmark for 19,000 Köln marks to the Teutonic Order. The shift of sovereignty from Denmark to the Teutonic Order took place on 1 November 1346.
Following its defeat in the Battle of Grunwald in 1410 the Teutonic Order fell into decline and its Livonian branch joined the Livonian Confederation established in 1422-35. The Teutonic lands in Prussia were split in two after the Peace of Thorn in 1466. The western part of Teutonic Prussia was converted into Royal Prussia, which became a more integral part of Poland. The monastic state in the east was secularized in 1525 during the Protestant Reformation as the Duchy of Prussia, a Polish fief governed by the House of Hohenzollern. The Livonian branch continued as part of the Livonian Confederation until its dissolution in 1561.