AACHEN (Fr. Aix-la-Chapelle; Dutch Aken), ancient city and spa, Rhenish Prussia, Germany, under the northern slopes of the Ardennes, on the Cologne-Brussels main line, 44m. W. by S. of Cologne. Pop. (1933) 162,99o. Its municipal boundaries co incide on the west with the frontiers of Belgium and Holland. In general appearance a prosperous, modern commercial town, it is full of mediaeval associations. The outer town is mainly new; while the ramparts of the old inner town are now promenades, with two ancient gates, Ponttor and Marschiertor, remaining. The hot sulphur springs have been celebrated for centuries. The con spicuous cluster of buildings in the centre of the city includes the cathedral and the Rathaus (town hall), a Gothic structure 1370) built on the ruins of Charlemagne's palace, which contains the magnificent coronation hall of the emperors (143ft. by 6I ft.). The two original towers, Granusturm and Glockenturm, were all but destroyed by fire in 1883 ; their restoration was completed in 1902. Near the Rathaus is the Grashaus, restored in 1889 to house the municipal archives. The cathedral, or minster, is in two distinct styles. The Romanesque Octagon, begun in 796, the finest extant Carolingian structure, was modelled on San Vitale at Ravenna, and consecrated by Pope Leo III. in 8o5. Emperor Otto III. rebuilt it, on the original lines, in 983, after its de struction by Norman raiders. It is surrounded on the first storey by a gallery (the Hochmtinster) with antique marble and granite columns, of various sizes, brought from Rome, Ravenna and Trier, removed by Napoleon to Paris, but restored after 1815. The mosaic representing Christ surrounded by "the f our-and twenty elders," which originally lined the cupola, was executed in 1881 from a 17th century copy of the ancient originals. The bronze west doors date from 804. Underneath the dome, tradition places the tomb of Charlemagne, said to have been opened by Otto III. in 1 000 and to have shown the emperor's body on a marble chair which was removed and long used for coronations. It is now in the gallery. The site of the tomb is marked by a stone slab, with the inscription Carlo Magno, and above it hangs the famous bronze chandelier presented by the emperor Barbarossa in 1168. In the Hungarian chapel, to the south-west, is the rich Cathedral Treasury, with fine mediaeval work such as the 13th century gold casket containing the relics of Charlemagne. The Gothic choir was added during the 14th and 15th centuries and contains the tomb of the emperor Otto III. The pulpit, a gift of emperor Henry II., dates from c. 1020. The cathedral possesses many relics, the more sacred of which are exhibited only once every seven years, when they attract large crowds.
The churches of St. Foillan (founded in the I2th century, but twice rebuilt, in the isth and 17th centuries, and restored in 1883) and St. Paul, with its beautiful stained-glass windows, are inter esting. The Suermondt museum contains fine pictures by early German, Dutch and Flemish masters. There are many fine streets, squares and public monuments. The fountain in the market square is surmounted by a statue of Charlemagne. In the principal square, Friedrich-Wilhelmplatz, is the Elisenbrunnen, with its colonnade and garden, the chief resort of visitors taking the baths and waters.
Since the working of extensive coalfields in the district almost every branch of iron industry has been carried on. Cloth, glass, needles and pins are important products. The suburb of Burt scheid, incorporated with Aachen in 1897, has old-established manufactures of cloth and needles and contains, among frequented thermal springs, the Schwertbad-Quelle (I7I°F.), the warmest spring in Germany.
ancient city and watering place of Aachen rep resents the Aquisgranum of the Romans, named after Apollo Granus, who was worshipped in connection with hot springs. As early as A.D. 765 King Pippin had a "palace" there, in which it is probable that Charlemagne was born. The greatness of Aachen was due to the latter, who between 777 and 786 built a magnificent palace on the site of that of his father, raised the place to the rank of the second city of the Empire, and made it for a while the centre of Western culture and learning. From the coronation of Louis the Pious in 813 until that of Ferdinand I. in 1531 the sacring of the German kings took place at Aachen; as many as 32 emperors and kings were crowned there. Late in the 12th century (1172-76) the city was surrounded with walls by order of the emperor Frederick I., to whom (in 1166) and to his grandson Frederick II. (in 1215) it owed its first important civic rights. In the i6th century Aachen began to de cline. It lay too near the French frontier to be safe, and too remote from the centre of Germany to be convenient, as a capital; and in 1562 the election and coronation of Maximilian II. took place at Frankfort-on-Main, a precedent followed till the ex tinction of the Empire. The city suffered gravely in the religious wars, being twice put under the ban of the Empire for Protestant ism. By the Treaty of Luneville (I8oi) Aachen was incorporated with France as chief town of the department of the Ruhr. In 1815 it was given to Prussia. In Nov. 1918, at the conclusion of the World War, Aachen was occupied for a period by Belgian troops.