Backed by the Archbishop of Salzburg, they conquered the territory around Metlika up to the Kolpa River in the southeast, the later White Carniola ("Bela krajina") region. Until 1209 the Counts of Weichselburg held extended possessions in the Windic March. Through a marriage to the last heiress Sophia of Weichselburg, the Counts of Andechs, then at the peak of their power as Margraves of Istria and Dukes of Merania came to dominate the territory. It was part of the dowry of Agnes of Merania, daughter of Duke Otto I of Andechs-Merania, upon her marriage with the Frederick II of Babenberg, son of Duke Leopold VI of Austria, in 1229. Frederick II thereafter called himself a "dominus Carniole" (Lord of Carniola) and succeeded his father as Duke of Austria and Styria in the following year. In 1248 the title was picked up by Duke Ulrich III of Carinthia, who had married Agnes of Merania after Frederick's death in 1246. When Duke Ulrich died in 1269, King Ottokar II of Bohemia occupied and unified Carniola, the Windic March, the valley of the Savinja, and the Slovenj Gradec as "the march" of his vast kingdom extending from the Baltic Sea to the Adriatic. After 1282, despite King Rudolf I's grant to his sons, Carniola and the Windic march were united under the control of the Meinhardiner duke Meinhard of Carinthia. During this period, the entity became known as the County in the March and Möttlig (Metlika). After 1374, the Windic March fell to the House of Habsburg. The Habsburgs however soon pawned it to the Counts of Cilli who remained the de facto rulers of the territory until their extinction in 1456. The Habsburgs retook the Windic March together with all other Cilli possessions in the Holy Roman Empire. They immediately reunited it with Carniola, and the Windic March thus ceased to be a separate political entity. The head of the House of Habsburg continued carrying the title of "Lord on the Windic March" in the grand title of the Emperor of Austria.