Settlements arose around the castles Köpenick (called 1209) and Spandau (called 1197) in the 12th century, around 1180/1200 the long-distance trading settlement of Cölln on the Spree island (first documented mention in 1237) and on the right bank of the Spree in Berlin (first documented mention in 1244). After the conquest of the Spree region around 1200, the increasing trade in this area prompted the Ascanian margrave brothers Johann I (1225–66) and Otto III. (1225-67) of Brandenburg between 1230 and 1240 for the granting of town charter to the already existing suburban settlements of Cölln and Berlin (after 1250 the name city was used); both soon grew together to form a twin city (Magdeburg city law). The oldest core of Berlin was around the former Nikolaikirche on Molkenmarkt (formerly Alter Markt; excavations 1956–58 and 1980–82).
The favor of the margraves and the particularly convenient location at the intersection of the waterway to the Elbe with the land connections to the North Sea and Baltic Sea ports as well as the long-distance trade routes from Leipzig and Magdeburg to the countries in the north and east allowed the twin cities to flourish quickly and were already in the In the second half of the 13th century, the expansion to include the Marienviertel with the Neuer Markt and the Marienkirche was necessary. Later the villages Wedding (1289), Reinickendorf (1397), Rosenfelde (1319; from 1699 Friedrichsfelde), Stralau (1358), Lichtenberg (1391) and Pankow (1370/75) were acquired; Woltersdorf (on the Barnim) and Tempelhof (on the Teltow) came under the joint ownership of Berlin and its sister city of Cölln in 1487 and 1435, respectively.
Berlin and Cölln quickly outstripped Köpenick and Spandau and, after the city of Brandenburg, formed the political center of the Mark (from 1307 union for defense and joint citizenship of the sister cities; from 1370 joint council that met in the common town hall on the “New Bridge”; 1432 unification); they joined the Hanseatic League (affiliation 1359/1442 documented), were several meeting places of the Brandenburg estates after 1345 and already in the 14th century provided by far the largest tax revenue of the Mark Brandenburg (1369 purchase of the margravial minting right). Rixdorf (now part of Berlin-Neukölln), first mentioned in 1360, was sold to the twin towns by the Order of St. John in 1435. Under the successors of the Ascanians (from 1319/20 Wittelsbacher, from 1373 Luxembourger) the city was able to strengthen its autonomy. Friedrich I. (1415 / 17–40) also restricted Berlin’s independence; Disputes between the patrician council and class groups that demanded participation in the city regiment also weakened the city’s political position. Elector Friedrich II., The Iron (1440–70), ended the dispute in 1442. He lifted the unification of the council and withdrew numerous privileges from the city (including the high judiciary). An uprising (“Berliner Unwille”; from 1447) ended in 1448 with the submission of the citizens and the curtailment of commercial privileges. As a sign of sovereign power, a castle similar to a moated castle was built on the Cölln Spree island in 1443–51. Johann Cicero (1455–99) was thefirst elector to havehis permanent residence in Berlin (from 1470).
The loss of trade privileges had hit the city hard and triggered an economic decline; Nevertheless, Berlin and Cölln had around 6,000 residents around 1450, and the population grew to around 11,000 by 1540. After the introduction of the Reformation (1539), the city received the patronage of the electoral church; in the abolished Franciscan monastery (13th century) the Latin school for the “gray monastery” was established. In the Thirty Years’ War (1618–48) occupations and looting by Swedish and imperial troops led to destruction and population losses in Berlin and Cölln (6,000 residents again in 1648); 1626–48, Spandau (1560–94 construction of the citadel) was surrounded by three bastions.
Under the great elector, Friedrich Wilhelm (1640–88), Berlin and Cölln were expanded into a fortress based on the Dutch model in 1658–83, including Friedrichswerder, founded in 1662 on the left bank of the Spree. Since 1674, the Dorotheenstadt was built on both sides of the 1647 esplanade “Unter den Linden” as a suburb and additional residence (grid-shaped floor plan). With the completion of the Oder-Spree Canal (built 1662–68), Berlin developed into an important transshipment port on the Hamburg – Breslau waterway and continued to expand. Berlin, which was developed into a baroque residence, continued to grow under the successors of the Great Elector. Friedrichstadt emerged (from 1688), the Stralauer Vorstadt on the right bank of the Spree above old Berlin (from 1690), the Königstadt (from 1690) and the Spandauer Vorstadt also on the right bank of the Spree below Old Berlin (from 1699). A settlement near Lietzenburg Palace that was built in 1701 was given the name Charlottenburg in 1705, as did the palace built between 1695 and 1712. After 1734, the Dorotheenstadt and especially the Friedrichstadt expanded due to immigrating German / foreign “colonists”. To the left of the Spree, in the south of Berlin and Cölln, the Köpenicker suburb emerged (from 1802 Luisenstadt).
In 1709, Frederick I, King of Prussia (from 1701), united Old Berlin, Cölln, Friedrichswerder, Dorotheenstadt and Friedrichstadt, including the suburbs, to form the “Residenzstadt Berlin” with 56,000 residents (including the garrison). His lavish courtship stimulated trade and commerce and made Berlin the cultural center of what was then (Brandenburg-) Prussia. This development found visible expression in the founding of the Academy of Arts (1696) and the Academy of Sciences (1700, on the initiative of G. W. Leibniz). King Friedrich Wilhelm I (1713–40) severely restricted the keeping of the court. The savings and the billeting of a strong garrison (1725: 12,000 men with 60,000 residents) changed the character of the city. Friedrich Wilhelm I and after him Friedrich II the Great (1740–86), As part of their mercantilist economic policy, they increasingly encouraged the establishment of factories and the influx of businesspeople. After 1685 (Edict of Potsdam), a large part of the new citizens of Berlin came from the Huguenot refugees, who also took on important positions in the army and in administration. Around 1720 the refugiés made up around 20% of Berlin’s population. The commercial economy that emerged during this period included state manufacturers for powder, iron, silver and porcelain as well as state-sponsored manufacturers for wool and cotton products and cloth weaving mills. From 1734 the ramparts were removed to gain building land, but the city was at the same time provided with a customs wall (demolished in 1866). The today’s gate names Brandenburger, Potsdamer, Hallesches Tor go back to them. In the Seven Years’ War (1756–63) Berlin was occupied by Austrian (1757) and Russian troops (1760). The Spandau fortress, which existed until 1907, was reinforced in 1806 and again in 1876–79.