mountain , former Duchy of Holy Roman Empire , on the right bank of the Rhine, today in the administrative districts Düsseldorf and Cologne in Germany .
In the 11th century, the Counts of Berg reached Westphalian territories east of Cologne. From 1161 these were divided between the senior branch of Berg and the junior branch of Altena (later Markus), who acquired the earldom of Cleves in 1368. The mountain line died out with the assassination of Engelbert I the Saint, the third member, in 1225 of the family to hold the Archdiocese of Cologne, and the title passed to the House of Limburg. In 1288, Count Adolf V began developing Düsseldorf (later Berg's capital) as a port. As a member of the House of Jülich, Gerhard VI. (died 1360) 1348 the heiress of Berg; In 1380 his son William was made duke; and in 1423 Duke Adolf Jülich also inherited, thus uniting the two duchies and the associated lands. When the male line died out in 1511, the lands passed to John III. Duke of Cleves. Berg became a leading iron and Textile Manufacturing Center in the 17th and 18th centuries. In 1806 Napoleon made it in his Rhine Confederation to a Grand Duchy , with his brother-in-law Joachim Murat as Grand Duke . Berg, along with Jülich, which had been annexed by the French, was awarded the Vienna Congress in 1814–15 Part of the Prussian Rhine Province .