BREISACH, or Altbreisach, a town of Germany, in the grand duchy of Baden, on the left bank of the Rhine, standing on a basalt rock 250 ft. above the river, 10 m. W. of Freiburg-im-Breisgau, and on the railway connecting that city with Colmar. Pop. (1900) 3537. It has a fine minster, partly Romanesque, partly Gothic, dating from the 10th to the 15th centuries; of its two principal towers one is 13th century Gothic, the other Romanesque. The interior is remarkable for its rich decorations, especially the wood-carving of the high altar, and for many interesting tombs and pictures. There is little industry, but a considerable trade is done in wines and other agricultural produce. On the opposite bank of the Rhine, here crossed by a railway bridge, lies the little town of Neubreisach and the fort Mortier.
Breisach (Brisiacum), formerly an imperial city and until the middle of the 18th century one of the chief fortresses of the Empire, is of great antiquity. A stronghold of the Sequani (a Gallic tribe, which occupied the country of the Doubs and Burgundy), it was captured in the time of Julius Caesar by Ariovistus and became known as the Mons Brisiacus. Fortified by the emperor Valentian in 369 to defend the Rhine against the Germans, it retained its position throughout the middle ages as one of the chief bulwarks of Germany and was called the “cushion and key (Kissen und Schlussel) of the German empire.” Its importance was such that it gave its name to the district Breisgau, in which it is situated. In 939 it was taken by the emperor Otto I., and after remaining in the exclusive possession of the emperors for two centuries, was strengthened and shared for a while between them and the bishops of Basel. In 1254 and 1262 the bishops obtained full control over it; but in 1275 it was made an imperial city by King Rudolph I., and at the beginning of the 14th century his son brought it definitively into the possession of the Habsburg monarchs, leaving the bishops but few privileges. In the Thirty Years’ War Breisach successfully resisted the Swedes, but after a memorable siege and a defence by General von Reisach, one of the most famous in military annals, it was forced to capitulate to Duke Bernhard of Saxe-Weimar on the 18th of December 1638. The endeavours of the emperor Ferdinand III. to retake it were fruitless, and by the peace of Westphalia (1648) Breisach was annexed to France. By the peace of Ryswick (1697) it was restored to Austria, when Louis XIV. built the town and fortress of Neubreisach on the left bank of the Rhine. Again in 1703 it fell into the hands of the French, owing to treachery, but was ceded to Austria by the peace of Rastatt (1714)—Yet again, in the War of the Austrian Succession, it was captured (1744) by the French, who dismantled the fortifications. They refortified it in 1796, and after passing, by the peace of Lunéville (1801), together with the Breisgau to the duke of Modena, Breisach was by the peace of Pressburg (1805) finally incorporated with Baden, when the fortifications were razed. During the Franco-German War (1870) Breisach suffered severely from bombardment directed against it from Neubreisach.