BERG (Thicatas Montensis), a former duchy of Germany, on the right bank of the Rhine, bounded on the N. by the duchy of Cleves, E. by the countship of Mark and duchy of Westphalia, and on the S. and W. by the bishopric of Cologne. Its area was about 1188 square miles. The district was raised in 1108 to the rank of a countship, but did not become a duchy till the 14th century, after it had passed into the possession of the Jfilich family. On the extinction of this house in 1609, Austria laid claim to the duchy as an imperial fief ; but, in keeping with the wishes of the inhabitants, it was administered conjointly by the electors of- Saxony and Brandenburg and the Elector Palatine till 1624, when by the Dusseldorf treaty the last of the three obtained the sole authority. In 1806 it was bestowed by Napoleon, along with the duchy of Cleves and other possessions, on Murat, who bore the title of grand duke of Berg ; and after Murat's elevation to the throne of Naples, it was transferred to Louis, the son of the king of Holland. By the Congress of Vienna in 1815 it was made over to Prussia, and now forms a flourishing part of her territory.