SENLIS, a town of France, in the department of Oise, lies on the right side of the Nonette, a left-hand affluent of the Oise, 34 miles north-north-east of Paris by the Northern Railway on the branch line (Chantilly-Crepy) connecting the Paris-Creil and Paris-Soissons lines. In 1881 it had only 6870 inhabitants ; but its antiquity, its historical monuments, and its situation in a beautiful valley, in the midst of the three great forests of Hallatte, Chantilly, and Ermenonville, render it interesting. Its Gallo-Roman walls, 23 feet high and 13 feet thick, are, with those of St Lizier (Ariege) and Bourges, the inost perfect in France. They enclose an oval arca 1024 feet long from east to west and 794 feet wide from north to south. At each of the angles formed by the broken lines of which the circuit of 2756 feet is composed stands or stood a tower ; number-ing originally twenty-eight, and now only sixteen, they are semicircular in plan, and up to the height of the wall are unpierced. The Roman city had only two gates ; the present number is five. The site of the prmtorium WaS afterwards occupied by a, castle occasionally inhabited by the kings of France from Clovis to Henry IV. and still represented by ruins dating from the llth, 13th, and 16th centuries. In the neighbourhood of Senlis the foundations of a Roman atnphitheatre, 138 feet by 105, have also been discovered. The old cathedral of Notre Dame (12th, 13th, and 166 centuries) was begun in 1155 on a vast scale ; but owing to the limited. resources of the diocese progress was slow and the transept was finished only under Francis I. The total length is 269 feet, but the nave (98 feet high) is shorter than the choir. At the west front there are three doors and two bell towers. The right-hand tower (256 feet high) is very striking : it consists, above the belfry stage, of a very slender octagonal drum with open-work turrets and a spire with eight dormer windows. The left-ha,nd tower, altered in the 16th century, is crowned by a balustrade and a sharp roof. In the side portals, especi-ally in the southern, the flamboyant Gothic' is displayed in all its delicacy. Externally the choir is extremely simple. In the int,erior the sacristy pillars with capitals of the 10th century are noteworthy. The episcopal palace, now an archmological museum, dates from the 13th century; the old collegiate church of St Frambourg was rebuilt in the 12th century in the style which became characteristic of the " saintes chapelles " of the 13th and 14th centuries; St Pierre, though enclosed by cavalry barracks, has preserved its two towers. The ecclesiastical college of St Vincent, occupying the old abbey of this name, has a very elegant church, the date of which has been greatly disputed by archmologists, who sometimes wrongly refer it to Queen Anne of Russia. The town-house and several private houses are also of architectural interest.

Senlis can be traced back to tho Gallo-Roman township of the Silvanectes which afterwards became Angustomagus. Christianity was introduced by St Rieul at the close of the 3d century. During the first two dynasties of France Senlis was a royal residence. After the dismemberment of the Carlovingian empire it belonged to the counts of Yermandois and then to tho royal domain, and obtained a communal charter in 1173. Its bishop, Guerin, elected in 1214, signalized himself at the battle of Bouvines. The burgesses took part in the Jacquerie of the 14th century, then sided with the Burgundians and the English, whom, however, they afterwards expelled. The Leaguers were there beaten by the duke of Longue-ville and La. None. In the thee of Henry IV. the local manufac-tures employed 200 masters and 4000 men, but all industrial activity has now disappeared. The bishopric was suppressed at the Revolu-tion, and this suppression was confirmed by the Concordat.