Brandenburg was one of seven Electorships of the Holy Roman Empire from the late medieval period, and controlled by the Bavarian royal Wittelsbach family from 1323 until 1415 when Emperor Sigismund granted it to the House of Hohenzollern. From the year 1442, Berlin became the residence of the Hohenzollerns. The Hohenzollerns embraced Lutheranism and acquired Ducal Prussia in 1525 and Albrecht of Brandenburg-Anspach secularized the Prussian holdings of the Teutonic Order. In 1618, Brandenburg then expanded its lands to include, among other territories, the Duchy of Prussia.

East Prussia, along the southeastern coast of the Baltic Sea, enclosed the bulk of lands of the now-extinct old Prussians. In prehistory, the east of the area was inhabited by the Eastern Balts. In time, the Western Balts consolidated into the Old Prussian nation, while the Eastern Balts, including the “Curonians,” consolidated into part of Latvia and Lithuania. Parts of the Baltic region remained wilderness for longer than anywhere else in Europe. About 350 BC Pytheas called the territory Mentenomon and the inhabitants Guttones, neighbors of the Teutones.

The territory was called “Brus” (“Prus”) in an 8th century German map. Vikings penetrated into the area in the 7th and 8th centuries and many were absorbed into the local population, especially in the bigger trade areas such as Truso and Kaup where they were said to travel nack and forth across the Baltic Sea. In expeditions launched by the Vikings and Danes later, many areas in Prussia including Truso and Kaup were destroyed.The old Prussian language belonged to the Western branch of the Baltic language group, but old Prussians spoke a variety of tongues, including German, and some related to modern Latvian and Lithuanian languages. Eastern Prussia from the 13th century on was almost entirely German as a result of German settlers. In 1457, Königsberg became the center of the Teutonic Order or Knights.

All across East Prussia, the landscape was dotted by old castles of the Teutonic Knights. During the siege of Acre in 1190, the Teutonic Order began as a hospital brotherhood to care for the many sick German crusaders who were denied medical care from others. It was turned into a military-monastic order in 1198, reflecting the involvement of the Hohenstaufen dynasty in the Holy Land. The order conquered territory in the Holy Land, and then, under grandmaster Hermann von Salza, Eastern Europe, where they rose to prominence. They were in Hungary by 1211-25. After 50 years of war, the knights had subdued the pagan Prussians, who had risen in revolt repeatedly and were now reduced to serfdom. The order allied themselves with the Polish dukes of Masovia and Silesia to both subjugate the Prussians and fight against Novgorod.

In the 13th century, more German emigrants arrived to settle the Prussian lands, and the Order was now an independently formed, noble political entity, and in 1243 and in 1263, the Pope allowed the knights to monopolize the grain trade. The Grand Master went to Venice after the fall of Acre in 1291, and then, after conquering Pomerelia in 1309, to Marienburg in Prussia, absorbing the Sword-Brethren in Livonia whose expansion had taken place further east. The knights administered their lands from Marienburg and granted considerable freedom to the cities, many of which joined the Hanseatic League. The Order was defeated in 1410 at Tannenberg by Poland and Lithuania, and after a revolt in its own territories it became a vassal of Poland.

Since 1618, both Brandenburg and Prussia were ruled by the Hohenzollerns, and beginning with the “Great Elector” Friedrich Wilhelm I after the devastation of the Thirty Years’ War, its brilliant leaders managed to take backwater Brandenburg to a pinnacle of power and prosperity in Europe. Since there was a sparsely populated Polish region sandwiched between two German regions. Brandenburg acquired another stretch of Baltic coast in eastern Pomerania in 1648 so as to bridge the territorial gap between Brandenburg and ducal Prussia. In the year 1657, Elector Friedrich Wilhelm finally succeeded, through minor wars and diplomacy, in severing the feudal link between his duchy and the Polish kingdom, and Poland conceded its loss of ducal Prussia in the treaty of Wehlau in 1657. With the peace of Oliva, 1660, Prussia was recognized as an independent duchy belonging to Brandenburg.

The main feature of Friedrich Wilhelm’s internal policy was the establishment of a system of permanent taxation, the revenue from which funded a strong, standing army. By the time the Great Elector’s grandson Friedrich Wilhelm I took power, the Prussian army amounted to 80,000 men, a whole 4% of the population, in a system which kept many armed men as a highly trained citizen army without damage to the economy. It had a highly effective officer corps and the first effective light cavalry. He also established a native arms industry. Aptly called the Soldier King, he achieved considerable success in his endeavors and managed to acquire Pomerania from Sweden.

Half of the army was made up of foreign mercenaries, and half were drafted from peasants throughout Prussia and Brandenburg. After training, they could return to their homes and regular jobs for ten months a year. Nobles served as well, but merchants were exempt. East Prussia had been destroyed by plague and famine when he took the throne, and he continued Prussia’s tradition of giving refuge to countless religious and political refugees from other regions of Europe and thereby repopulated the devastated land. 20,000 Salzburg Protestant exiles and 8,000 French Huguenots who had arrived in 1685 and 1732 mingled with immigrants from French Switzerland, Nassau, the Pfalz, Magdeburg and Halberstädt, and the total population in East Prussia between 1713 and 1740 rose from 400,000 to 600,000 inhabitants.

During his reign, Friedrich Wilhelm kept his loyalty to the Holy Roman Empire and its emperor, Karl VI. He supported the Habsburgs against France in the War of Polish Succession. He also supported the Pragmatic Sanction, an agreement that all of the Electors in the Empire would support the succession of Karl VI’s daughter, Maria Theresa, to the throne of Austria, should he have no male heir. Friedrich Wilhelm I died in 1740, the same year that Karl VI died. By the end of his reign, barely 5% of the kingdom’s revenue was dedicated to upkeep of the royal family and state functions, while in France, for example, the royal family spent up to 50% of the country’s revenue on their upkeep. Friedrich Wilhelm I was therefore able to bequeath a strong economy with a cash surplus and Europe’s best-trained army to his 28-year-old son, Friedrich II, the Great.