Albi (älbēˈ) [key], town (1990 pop. 48,707), capital of Tarn dept., S France, in Languedoc, on the Tarn River. A commercial center, its has glassworks and food-processing, textile-manufacturing, and tourist industries. An old Roman city (Albiga), it became an episcopal see in the 5th cent. It was the center of the heresy to which it gave its name (see Albigenses). The old part of the city, known as the ville rouge because of its red-brick buildings, is a marvel of medieval architecture. The huge Gothic Cathedral of Sainte-Cécile, begun in 1282, resembles a fortress rather than a church. Other structures include the episcopal palace (13th–15th cent.) and an 11th-century bridge. The birthplace of Toulouse-Lautrec, Albi has an art museum containing much of his work.