DUREN (the ancient Marcodurum), a town of Rhenish Prussia, capital of a cognominal circle on the Roër, here crossed by a stone bridge, and on the Cologne and Aix-la-Chapelle railway, 18 miles E. by N. of the latter city. Pop. (1849) 8054. It has several Roman Catholic and Protestant churches, a Roman Catholic gymnasium, and three nunneries. The manufactures are extensive, and include cotton and woolen stuffs and cassimeres, cutlery, nails, wire, and other hardware goods; soap, leather, paper, and brandy. Charlemagne held two diets here in 775 and 779, when on his way to attack the Saxons. It afterwards became an imperial city, and was taken by assault and burned by Charles V. in 1543. In 1794 it fell into the hands of the French, and was made the capital of the department of Roër, but was ceded to Prussia in 1814.