Prussia is a historical region in Central Europe extending from the south-eastern coast of the Baltic Sea to the Masurian Lake District. It is now divided between Poland, Russia, and Lithuania. The former German state of Prussia derived its name from the region.
Parts of the Baltic region retained large wilderness areas for longer than anywhere else in Europe. In prehistory, the east of the area was inhabited by the Eastern Balts, whilst the Western Balts inhabited the Sambian peninsula and the areas to the west. Over time, the Western Balts consolidated into the Old Prussian nation, while the Eastern Balts of the area, including the Curonians, consolidated into (a part of) the Latvian and Lithuanian nations.
About 350 BC Pytheas called the territory Mentenomon and the inhabitants Guttones, neighbors of the Teutones. A river to the east of the Vistula was called the Guttalus (also Guthalus) and was assumed to have been the Memel or the Alle or Pregel river.
The Vikings started to penetrate into Eastern Europe in the 7th and 8th centuries. The largest trade centres of the Prussians, such as Truso and Kaup, seem to have absorbed a number of Norsemen. Prussians were known to go from Truso to Birka across the Baltic Sea.
At the end of the Viking Age, the son of Danish king Harald Bluetooth and Canute the Great launched several expeditions against the Prussians, which resulted in far-spread destruction of many areas in Prussia including the destruction of Truso and Kaup. They failed to establish a firm foothold in Prussia, however. A Viking (Varangian) presence in the area was "less than dominant and very much less than imperial".
The Old Prussians spoke a variety of languages, with Old Prussian belonging to the Western branch of the Baltic language group. Related, but not mutually intelligible, are the modern representatives of the Baltic languages, the Latvian and Lithuanian languages, from the East Baltic branch. Previous historians had documented the Prussian tribes as easterners, with Tacitus referring to them as the Aesti. The territory was called Brus in the 8th century map of the Bavarian Geographer. Adalbert of Prague, a Christian missionary sent with guards by Boleslaw I of Poland to convert the Prussians, was killed by a Prussian priest in 997.
In the 13th century Konrad of Masovia had called for Crusades and tried for years to conquer Prussia, but failed. Thus the pope set up further crusades. Finally he invited the Teutonic Knights to fight the inhabitants of Prussia in exchange for a fief of Chełmno Land. Prussia was conquered by the Teutonic Knights during the Prussian Crusade and administered within their monastic state.
With the Second Peace of Thorn (1466), Prussia was divided into eastern and western lands. The western part became the autonomous Royal Prussia within the Kingdom of Poland, while the eastern part of the monastic state became a fief of Poland. In 1492, a life of Dorothea of Montau, published in Marienburg (Malbork), became the first printed publication in Prussia.
During the Protestant Reformation, endemic religious upheavals and wars occurred, and in 1525, the last Grand Master of the Teutonic Knights, Albert of Brandenburg, a member of a cadet branch of the House of Hohenzollern, adopted the Lutheran faith, resigned his position, and assumed the title of "Duke of Prussia." In a deal partially brokered by Martin Luther, the Duchy of Prussia became the first Protestant state and a vassal of Poland. The ducal capital of Königsberg, now Kaliningrad, became a centre of learning and printing through the establishment of the Albertina University in 1544.
Ducal Prussia passed to the senior Hohenzollern branch, the ruling Margraves of Brandenburg, in 1618, and Polish sovereignty over the duchy ended in 1657 with the Treaty of Wehlau. Because Ducal Prussia lay outside of the Holy Roman Empire, Frederick I achieved the elevation of the duchy to the Kingdom of Prussia in 1701. The former ducal lands became known as East Prussia. Royal Prussia was annexed from the Polish-Lithuanian Commonwealth by the Kingdom of Prussia during the 18th century Partitions of Poland and administered within West Prussia.
Though the Kingdom of Prussia was a member of the German Confederation from 1815 to 1866, the provinces of Posen and Prussia were not a part of Germany until the creation of the German Empire in 1871 during the unification of Germany.
By the Treaty of Versailles, some territories of West Prussia and the Province of Posen that had belonged to the Prussian kingdom and the German Empire were ceded to the Second Polish Republic. East Prussia, minus the Memelland, received some districts of former West Prussia and remained within the German Weimar Republic.
According to the Potsdam Conference in 1945 after World War II, the Prussian region was divided between Poland and the Soviet Union. Western Prussia (West Prussia / Royal Prussia) and the East Prussian lands of Warmia and Masuria are in Poland, while northern East Prussia was divided between the Russian and Lithuanian Soviet republics. The German state of Prussia, of which the Prussian region was but a small part, was dissolved in 1947.