Welf was heir to the Duchy of Bavaria. He also exerted a protectorate over the Duchy of Gascony. Most of the lands of the former Grand Duchy were re-annexed by Russia. It was formerly a Brythonic kingdom and subsequently a royal duchy. Later it was part of the territory of the Grand Duchy of Lithuania. Russia demanded to gain all territories of the Duchy of Warsaw. Heidelberg fell to the Grand Duchy of Baden in 1803. Carloman received rule over the Duchy of Bavaria. The Prussian Partition included a portion separated as the Grand Duchy of Posen. Northern Estonia became the Swedish Duchy of Estonia. The first of several divisions of the duchy of Bavaria occurred in 1255. The lands around Rouen became the core of the later duchy of Normandy. Brest became part of the Grand Duchy of Lithuania in 1319. Salzburg is coterminous with the former Austro-Hungarian Duchy of Salzburg (the former Archbishopric). Prince Charles, a lover of his Duchy Originals biscuits.