Otto III, Margrave of Brandenburg
Otto III, nicknamed the pious (1215 – 9 October 1267 in Brandenburg an der Havel) was Margrave of Brandenburg jointly with his elder brother John I until John died in 1266. Otto III then ruled alone, until his death, the following year.
Otto III
1220–1267
1215
9 October 1267
Brandenburg an der Havel
Matilda of Lusatia
The reign of these two Ascanian margraves was characterized by an expansion of the margraviate, which annexed the remaining parts of Teltow and Barnim, the Uckermark, the Lordship of Stargard, the Lubusz Land and parts of the Neumark east of the Oder. They consolidated the position of Brandenburg within the Holy Roman Empire, which was reflected in the fact that in 1256, Otto III was a candidate to be elected King of the Germans. They founded several cities and developed the twin cities of Cölln and Berlin. They expanded the Ascanian castle in nearby Spandau and made it their preferred residence.
Before their death, they divided the margraviate in a Johannine and an Ottonian part. The Ascanians were traditionally buried in the Lehnin Abbey in the Ottonian part of the country. In 1258, they founded a Cistercian monastery named Mariensee, where members of the Johannine line could be buried. In 1266, they changed their mind and founded a second monastery, named Chorin, 8 km southwest of Mariensee. John was initially buried at Mariensee; his body was moved to Chorin in 1273.
After the Ottonian line died out in 1317, John I's grandson Waldemar reunited the margraviate.
Life[edit]
Regency and guardianship[edit]
Otto was the younger son of Albert II of the Brandenburg line of the House of Ascania and Mechthild (Matilda) of Lusatia, daughter of Count Conrad II of Lusatia, a junior line of the House of Wettin. Since both Otto and his two-year older brother John I 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 Bernard 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 Hernry I.[1] The Archbishop of Magdeburg then traveled 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 presented an opportunity for Count Palatine Henry V to get involved. Emperor Frederick II managed to prevent a feud, urging them to keep the peace.
After Matilda died in 1225, the brothers ruled the Margraviate of Brandenburg jointly. John I was about twelve years old at the time, and Otto III was ten. They were knighted on 11 May 1231 in Brandenburg an der Havel and this is generally taken as the beginning of their reign.[2][3]