Regency and guardianship John was the elder son of
Albert II of the Brandenburg line of the House of Ascania and Mechthild (Matilda), the daughter of Margrave
Conrad II of Lusatia, a junior line of the
House of Wettin. Since John and his two-year-younger brother
Otto III were minors when their father died in 1220, Emperor
Frederick II transferred the regency to Archbishop
Albert I of Magdeburg. The guardianship was taken up by the children's first cousin once removed, Count
Henry I of Anhalt, the older brother of Duke
Albert I of Saxony, a cousin of Albert II. As the sons of Duke
Bernhard III of Saxony, they were the closest relatives, and Henry had the older rights. In 1221, their mother, Countess Matilda, purchased the regency from the Archbishop of Magdeburg for 1900 silver
Marks and then ruled jointly with Henry I. The Archbishop of Magdeburg then travelled to Italy to visit Emperor Frederick II, and Duke Albert I of Saxony attempted to grab power in Brandenburg, causing a rift with his brother Henry I. The Saxon attack allowed Count Palatine
Henry V to get involved. Emperor Frederick II prevented a feud, urging them to keep the peace. After Matilda died in 1225, the brothers jointly ruled the Margraviate of Brandenburg. John I was twelve at the time, and Otto III was ten. They were knighted on 11 May 1231 in
Brandenburg an der Havel, which is generally taken as the beginning of their reign.
Domestic policies , around 1320 After the death of Count Henry of Brunswick-Lüneburg in 1227, the brothers supported his nephew, their brother-in-law
Otto the Child, who was only able to prevail against Hohenstaufen's claims and its vassals by force of arms. In 1229, there was a feud with former regent Archbishop Albert, which ended peacefully. Like their former opponents and defenders, they appeared at the Diet of Mainz in 1235, where the
Public Peace of Mainz was proclaimed. After the dispute over the kingship between
Conrad IV and
Henry Raspe the brothers recognized
William II of Holland as King in 1251. They first exercised Brandenburg's electoral privilege in 1257, when they voted for King
Alfonso X of Castile. Although Alfonso was not elected, the fact that they could vote illustrates the growing importance of Brandenburg, founded only a century earlier, in 1157, by
Albert the Bear. When John and Otto came to power, Brandenburg was considered an insignificant little principality on the eastern border. By the 1230s, the Margraves of Brandenburg had gained the heritable post of Imperial Chamberlain and the indisputable right to vote in the election of the
King of the Germans.
Developing the country and
Barnim plateaus, around 1250 (
Vrankenvorde) to city status in 1253 John I and his brother Otto III developed the territory of their margraviate and expanded market towns and castles, including
Spandau,
Cölln and
Prenzlau, into towns and centers of commerce. They also expanded
Frankfurt an der Oder, and John I awarded it city status in 1253.
The Teltow War and the Treaty of Landin Between 1230 and 1245, Brandenburg acquired the remaining part of
Barnim and the southern
Uckermark up to the
Welse river. On 20 June 1236, the Margraviate acquired the Lordships of
Stargard,
Beseritz, and
Wustrow by the
Treaty of Kremmen from Duke
Wartislaw III of Pomerania. Later that year, the brothers initiated the construction of
Stargard Castle to secure the northernmost part of their territory. From 1239 to 1245, the brothers fought the
Teltow War against the
Margraves of Meissen of the
House of Wettin. At stake was a
Slavic castle at
Köpenick, a former headquarters of the Sprewanen tribe, located at the confluence of the
Spree and
Dahme rivers. At the time, it was just east of
Berlin; today, it is part of the city. It dominated the
Barnim and
Teltow areas. In 1245, the brothers managed to take the castle at Köpenick and a fortress at
Mittenwalde. From this base, they could expand further to the east. In 1249, they acquired the
Lubusz Land and reached the river
Oder. In 1250, the brothers closed the
Treaty of Landin with the Dukes of Pomerania. Under this treaty, they received the northern part of the Uckermark (), north of the Welse River and the districts of
Randow and Löcknitz in exchange for the half of the Lordship of
Wolgast that John I had received as
dowry from King
Waldemar II of Denmark when he married his first wife, Sophia. This treaty is considered the birth of the Uckermark as a part of Brandenburg.
Policies to stabilize the Neumark During the first third of the 13th century, German settlers were recruited by Duke
Leszek I the White to settle in
Neumark. After he died in 1227, the Polish central government collapsed, allowing the Margraves of Brandenburg to expand eastwards. They acquired land east of the
Oder and expanded their domain further east to the river
Drawa and north to
Persante. In 1257, John I founded the town of
Landsberg (now called
Gorzów Wielkopolski) as an alternative river crossing across the
Warta, competing with the crossing in the Polish town of
Santok, detracting from the considerable revenues Santok made from foreign trade (customs duties, fees from the market operation and storage fees), similar to the way
Berlin had been founded to compete with
Köpenick. In 1261, the Margraves purchased
Myślibórz (
German:
Soldin) from the
Knights Templar and began developing the town into their power center in the Neumark. The Margraves used the tried and tested Ascanian policy of founding monasteries and settlements to stabilise their new possessions. As early as 1230, they supported the Polish Count Dionysius Bronisius when he founded the
Cistercian Paradies Monastery near
Międzyrzecz (
Meseritz) as a
filiation of the monastery at Lehnin. Their cooperation with the Polish count provided border security against Pomerania and prepared the area's economy for integration into the Neumark. Among the settlers in the Neumark was the
von Sydow family, who were later ennobled. The small town of
Cedynia (
Zehden; today in the Polish Voivodeship of
West Pomerania) was enfeoffed to the noble
von Jagow family. The historian Stefan Warnatsch has summarized this development and the attempts of the Ascanians to gain access to the
Baltic Sea from the middle Oder and the Uckermark as follows:
The great success of the territorial expansion in the 13th century was mainly due to the great-grandsons of Albert the Bear. The design of their reign reached much further spatially and conceptually than their predecessors. According to Lutz Partenheimer:
[around 1250], the Ascanians had pushed back their competitors from Magdeburg, Wettin, Mecklenburg, Pomerania, Poland and the smaller competitors on all fronts. Other settlements in the area, such as
Spandau and
Köpenick, date back to the Slavic period (from about 720). These naturally had a greater strategic and political importance than the young merchant towns Cölln and Berlin. For a long time, the border between the territories of the
Slavic tribes Hevelli and Sprewanen crossed straight through the area of today's Berlin. Around 1130,
Spandau was an eastern outpost of the
Hevelli under
Pribislav. When Pribilav died in 1150, Spandau fell to Brandenburg under the terms of an inheritance treaty between
Pribislav and
Albert the Bear. Brandenburg did not acquire Köpenick until 1245.
Residence at Spandau , the scene of a battle against Magdeburg in 1229 In 1229, the Margraves of Brandenburg lost a battle against their former guardian, the archbishop of Magdeburg at the
Plauer See, close to their residence in
Brandenburg an der Havel. The escaped to the fortress at Spandau. In the following years, the brothers made Spandau their preferred residence, next to
Tangermünde in the
Altmark. Between 1232 and 1266, seventeen stays at Spandau have been documented, more than at any other town. Albert the Bear probably expanded the fortress island at Spandau eastwards before or shortly after his victory against a certain
Jaxa (this was probably
Jaxa of Köpenick) in 1157. Towards the end of the 12th century, the Ascanians moved the fortress about a kilometer to the North, to the location of today's
Spandau Citadel, probably because of a rising ground water table. The presence of an Ascanian fortress on this site in 1197 has been established. John I and Otto III expanded the fortress and promoted the
civitas in the adjacent settlement. They gave it city rights in 1232 or earlier. They founded the
Benedictine nunnery of St. Mary in 1239. The
Nonnendammallee, one of the oldest streets in Berlin and as
Nonnendamm part of a
trade route as early as the 13th century, is still a reminder of the former nunnery
Expansion of Cölln and Berlin ) around 1230 in Berlin, founded around 1220/1230, picture from 1740 According to the current state of research, no evidence has been found that a Slavic settlement existed in the area around the twin towns of Berlin and Cölln. The
ford across the largely swampy Berlin Glacial Valley gained importance during the Slavic-German transition period, when John I and Otto III settled the sparsely populated plateaus of Teltow and Barnim with local Slavs and German immigrants. According to Adriaan von Müller, the strategic importance of Cölln and Berlin, and the reason for the foundation was probably to form a counterweight to Köpenick, a secure trading hub held by the
Wettin (dynasty) with its own trade roues to the north and east. The broad ford across two or even three river arms away could best be protected by fortified settlements on both river banks. The Margraves protected the route to
Halle across the northwestern Teltow plateau by a chain of
Templar villages:
Marienfelde,
Mariendorf, Rixdorf and
Tempelhof. After the Ascanians defeated the Wettins in the
Teltow War of 1245, the importance of Köpenick decreased, took an increasingly central position in the developing trading network. According to Winfried Schich, we can assume the "Berlin and Cölln owe their development as urban settlements to the structural changes in this area due to the expansion during the
High Middle Ages, which led both to a denser population and a reorganization of long-distance trade routes. [...] The diluvial plateaus of Teltow and Barnim with their heavy and relatively fertile soils, were systematically settled and put under the plow during the reign of Margraves John I and Otto III." During the first phase of settlement, the lowland areas along the river with their lighter soils seem to have been the preferred places of settlement. According to the of 1280, Berlin and other places were "built" () by John I and Otto III. Since their reign had started in 1225, the period around 1230 is considered the founding period of Berlin. Recent archeological research has uncovered evidence of late 12th century
market towns in both Cölln and Berlin. Ninety graves were excavated in the
St. Nicholas Church, the oldest building in Berlin, with foundations dated 1220-1230 and some of these graves could also be from the late 12th century. This implies that the two Margraves did not actually found the cities of Cölln and Berlin, although they did play a decisive rôle in the early expansion of the cities. Among the privileges granted to the two cities by the Margraves were Brandenburg Law (including absence of tolls, free exercise of trade and commerce, hereditary property rights) and in particular the
staple right, which gave Cölln and Berlin an economic advantage of Spandau and Köpenick. The Margraves gave the
Mirica, the Cölln Moor, with all usage rights to the citizens of Cölln. The connection of the Margraves with Berlin is also evidenced by their choice of Hermann von Langele as their
confessor. This Hermann von Langele was the first known member of the
Franciscan convent at Berlin. He is mentioned as a witness in a deed issued by the Margrave in Spandau in 1257. == Inheritance and descendants ==