Amiens (ämyăNˈ) [key], city (1991 pop. 136,234), capital of Somme dept., N France, in Picardy, on the Somme River. It is a rail hub and a large market for the truck farming carried on in the surrounding Somme marshlands. Also an important textile center (since the 16th cent.), it has been particularly famous for its velvet. Other products are chemicals, soap, tires, and electrical equipment. Originally a Gallo-Roman town, it was an episcopal see from the 4th cent. The historic capital of Picardy, it was overrun and occupied by many invaders. It was conquered by Henry IV in 1597. There, in 1802, the Treaty of Amiens was signed. It was severely devastated in both World Wars and has been rebuilt since 1945, largely in the medieval style. Of interest is the Cathedral of Notre Dame (begun c.1220), the largest Gothic cathedral in France. It is 470 ft (143 m) long and has a nave 140 ft (43 m) high; the transept dates from the 14th cent.; the spire (370 ft/113 m high) and the large rose window were added in the 16th cent.