ALESSAN DEJA, the principal fortress and town of the province of the same name in the n. of Italy, is situated in a marshy country near the confluence of the Bormida and Tanaro. It was built in 1168 by the inhabitants of Cremona, Milan, and Placentia, as a bulwark against emperor Frederick I. Its original name was exsarea, but it was afterwards called A. in honor of pope Alexander III., who established a bishopric in it. Designed at first as a fortress to guard the passage of the Bormida and Tanaro, and be ing the central point of intercourse between Genoa, Milan, and Turin, the town has frequently been the object of sanguinary strife. It was taken and plundered in 1522 by duke Sforza; besieged, but without success, by the French, under the prince of Conti, in 1637; and agaii taken, in spite of an obstinate resistance, by prince Eugene in 1707. After the prostration of Austria at the battle of Marengo in 1800, Bonaparte concluded an armistice at A. with his enemies, according to which, upper Italy, as far as the
Mincio, was ceded to the French, with twelve fortresses. It was the principal armory of the Piedmontese during the insurrection of the Lombardo-Venetian states in 1848-9, when many new fortifications were added to it. At present, the citadel is one of the strongest fortresses in Europe; of enormous size, larger, it is said, than many a town, and in the event of a war in Italy, the whole surrounding country can be inundated by means of the sluices of the Tanaro. A. contains, exclusive of the garrison (1871), 29,102 inhabitants, who carry on a considerable trade in linens, woolens, silk fabrics, stock ings, hats, etc. The culture of flowers is also much attended to. Two fairs are held in A. annually, which are largely frequented.