Albert II, Margrave of Brandenburg

The Altmark belonged to Brandenburg, and his older brother Otto II claimed that this implied that the Ascanians owned Arneburg.

After Philip's assassination in 1208, however, he changed sides, because Emperor Otto IV had assisted him in securing the Margraviate against the Danes, and had confirmed Ascanian ownership of Brandenburg in a deed in 1212.

Albert II definitively secured the regions of Teltow, Prignitz and parts of the Uckermark for the Margraviate of Brandenburg, but lost Pomerania to the House of Griffins.

Stephan Warnatsch describes Otto I's children as follows:[2] [They] continued the territorialisation drive that had been initiated [by their father] and, from the end of the 12th Century, as the influx of settlers grew stronger, and, consequently, more people were available to develop the territory, started to expand into the areas of Ruppin, and in particular, Barnim and Teltow.

In 1205, Albert married Matilda of Groitzsch (1185–1225), daughter of the Count Conrad II of Lusatia,[1] a member of the House of Wettin, and wife Elizabeth, from the Polish Piast dynasty.