**TONGRES** (in Flemish TONGEREN). - A city and ancient diocese in Limburg (Belgium), on the banks of the river Ieker, a tributary of the Meuse. It is the ancient *Atuatuca Tungrorum*, capital of the *Civitas Tungrorum* in the Roman province of "Germania inferior."
The diocese was established as early as the 3rd century, but the first recorded bishop is St. Servatius (344-84), who took refuge in Maastricht (q.v.). With the invasion of 406, the city lost its importance and was administered by representatives of the Bishop of Liège. A serious fire damaged it in 1677.
The ancient cathedral of Notre-Dame is in Gothic style from the 13th century, built over the earlier Romanesque church, of which the crypt and the 12th-century cloister survive, the latter restored in the 14th century; the apse and the last part of the three naves with their chapels date from the 14th-15th centuries; the transept is from 1456; the porch, façade, and high tower were built between 1444 and 1586. The brass Easter candlestick is the work of J. J. De Dinant; remarkable is a Romanesque crucifix from the early 12th century. The attached treasury preserves an ivory from the 6th century depicting St. Paul, with on the reverse a list of bishops of Liège from 1840 to 1956; originally this ivory was part of a diptych containing on the right the figure of St. Peter, now preserved in the Cinquantenaire Museum in Brussels, but partially restored (J. Helbig, *L'art mosan depuis l'Introduction du christianisme jusqu'à la fin du XVIIIe siècle*, Brussels 1906, p. 23; M. Laurent, *Les ivoires prégotihques conservés en Belgique*, ibid. 1912, pp. 6-7, fig. 2); there are also two evangelists, one from the 9th century and the other from the 11th; a triptych with the relic of the Holy Cross from about 1170. Notable also are the church of the hospital of St. James (1660-62) and that of St. Catherine, built in 1294 but restored with the attached *béguinage* of 1257.
Pope Pius XI, by an apostolic letter of 20 February 1931, raised the ancient cathedral of Notre-Dame to the dignity of a minor basilica, dedicated to the Blessed Virgin Mary "Causae nostrae laetitiae" (AAS, 23 [1931], pp. 373-75).
Excavations carried out in 1912 in Tongres confirmed its Roman origin and that its circuit of walls of that period was more extensive than the medieval one. Important studies on Tongres and its monuments have been published in the *Bulletin de la Société scientifique du Limbourg* since 1906.