SENLIS, a town of northern France, capital of an arrondisse ment in the department of Oise, on the right side of the Nonette, a left-hand affluent of the Oise, 34 m. N.N.E. of Paris by the Northern railway on the branch line (Chantilly-Crepy) connecting the Paris-Creil and Paris-Soissons lines. Pop. (1931) 5,835. Senlis can be traced back to the Gallo-Roman township of the Sil vanectes, which afterwards became Augustomagus. Christianity was introduced by St. Rieul probably about the close of the 3rd century. During the first two dynasties of France Senlis was a royal residence and generally formed part of the royal domain; it obtained a communal charter in 1173. In the middle ages local manufactures, especially that of cloth, were active. The bur gesses took part in the Jacquerie of the 14th century, then sided with the Burgundians and the English; whom they afterwards expelled. The Leaguers were there beaten in 1589 by Henry I., duke of Longueville, and Francois de La Noue. The bishopric was suppressed at the Revolution.
Senlis lies in a valley, in the midst of the three great forests of Hallatte, Chantilly and Ermenonville. It has Gallo-Roman walls, 23 ft. high and 13 ft. thick. They enclose an oval area 1,024 ft. long from east to west and 794 ft. wide from north to
south. At each of the angles formed by the broken lines, of which the circuit of 2,756 ft. is composed, stood a tower; originally 28, there remain 16 ; they are semicircular in plan, and up to the height of the wall are unpierced. The Roman city had two gates; there are now five. The site of the praetorium was afterwards occupied by a royal castle, of which there are ruins dating from the 11th, 13th and i6th centuries. Near Senlis the foundations of a Roman amphitheatre have also been discovered. The old cathedral of Notre Dame (12th, 13th and i6th centuries) was begun in 1155 on a vast scale, but the transept was finished only under Francis I. At the west front there are three doorways and two bell towers, of which the right-hand tower (256 ft. high) consists, above the belfry stage, of a very slender octagonal drum with open-work turrets and a spire with eight dormer windows. The episcopal palace dates from the 13th century; the old col legiate church of St. Frambourg was built in the 12th century in the style which became characteristic of the "saintes chapelles" of the 13th and 14th centuries; St. Pierre (chiefly of the 15th and i6th centuries) serves as a market.