The House of Ascania () was a dynasty of German rulers. It is also known as the House of Anhalt, which refers to its longest-held possession, Anhalt. The Ascanians are named after Ascania (or Ascaria) Castle, known as Schloss Askanien in German, which was located near and named after Aschersleben. The castle was the seat of the County of Ascania, a title that was later subsumed into the titles of the princes of Anhalt. History The earliest known member of the house, Esiko, Count of Ballenstedt, first appears in a document of 1036. He is assumed to have been a grandson (through his mother) of Odo I, Margrave of the Saxon Ostmark. From Odo, the Ascanians inherited large properties in the Saxon Eastern March. Esiko's grandson was Otto, Count of Ballenstedt, who died in 1123. By Otto's marriage to Eilika, daughter of Magnus, Duke of Saxony, the Ascanians became heirs to half of the property of the House of Billung, former dukes of Saxony. Otto's son, Albert the Bear, became, with the help of his mother's inheritance, the first Ascanian duke of Saxony in 1139. However, he soon lost control of Saxony to the rival House of Guelph. Albert inherited the Margraviate of Brandenburg in 1157 from its last Wendish ruler, Pribislav, and he became the first Ascanian margrave. Albert, and his descendants of the House of Ascania, then made considerable progress in Christianizing and Germanizing the lands. As a borderland between German and Slavic cultures, the country was known as a march. In 1237 and 1244, two towns, Cölln and Berlin, were founded during the rule of Otto and Johann, grandsons of Margrave Albert the Bear. Later, they were united into one city, Berlin. The emblem of the House of Ascania, a red eagle and bear, became the heraldic emblems of Berlin. In 1320, the Brandenburg Ascanian line came to an end. After the Emperor had deposed the Guelph rulers of Saxony in 1180, Ascanians returned to rule the Duchy of Saxony, which had been reduced to its eastern half by the Emperor. However, even in eastern Saxony, the Ascanians could establish control only in limited areas, mostly near the River Elbe. In the 13th century, the Principality of Anhalt was split off from the Duchy of Saxony. Later, the remaining state was split into Saxe-Lauenburg and Saxe-Wittenberg. The Ascanian dynasties in the two Saxon states became extinct in