CHÂLONS-SUR-MARNE, Diocese of. – A city and department of the Marne, in Champagne, suffragan of Reims. Formed by a vast plain watered by the Marne, the region of Châlons has been crossed repeatedly over the centuries by armies that invaded northern France. In the 4th century, Châlons was already one of the most notable cities of Belgica Secunda: Durocatalaunos in the Antonine Itinerary. The Catalaunian Fields are known for the battle between Aetius and Attila in the year 451.
The spread of Christianity in the region of Châlons dates back to the 4th century. The diocese of Châlons has an episcopal list known from a copy by Mabillon that Delisle identified in a Sacramentary already existing in the episcopal library of Châlons. Another text of the catalogue is preserved by Robert of Torigni. The first-hand copy by Mabillon extended as far as Guido (1048), then continued until the 14th century, but also records four bishops of the 17th–18th centuries. At the head of the list is Mermino, whose sanctuary is mentioned by Gregory of Tours (In gloria confessorum, 65), noted on 5 August in the Hieronymian Martyrology, though his Passio (BHL, 5907–14) is of no value. Also celebrated is St Alpino, disciple of St Lupus of Troyes, and Ildigrim, bishop of Châlons in 802, who, however, contributed little to the evangelization of Frisia and Saxony; he inherited from his brother the abbey of Werden on the Ruhr, where he was buried in 827.
In the 9th century, the bishops of Châlons became lords of the county. In 1111, the papal legate Cono convened a council at Châlons against Henry V, who had been excommunicated by Paschal II during the Investiture Controversy. Subsequently, other synods were held at Châlons in 1559, 1631, 1647, etc. The fine Gothic cathedral is dedicated to St Stephen the Protomartyr, consecrated by Eugenius III in 1147, restored in the 13th century, with additions from the 17th; the interior has three naves with large stained-glass windows from the 13th–16th centuries.
Francis I fortified the city with powerful works, but Châlons suffered greatly during the religious wars of the 16th century. The Parliament of Paris moved there in 1592.
Within the diocesan territory is the shrine of Our Lady of l’Épine, recently granted the title of minor basilica. The area of the diocese is 6,476 km² and includes the entire department of the Marne (except the arrondissement of Reims), with a population of 217,127, of whom 183,000 are Catholic (1948).
Suppressed by the Concordat of 1801 and annexed to that of Meaux, the diocese was re-established in 1882 and, as in the past, made suffragan of Reims.
It is divided into 10 archpriestships and 5 deaneries, with 475 parishes, 268 diocesan priests, and 9 religious; the patron of the diocese is St Memmius. This area, exposed by its geographical position to the dangers of armed conflict, is one of those French dioceses where the war of 1914–18 caused the greatest destruction, increased recently by the last war, which destroyed the parishes of Hurlus, Le Mesnil-les-Hurlus, Perthes-les-Hurlus, Ripont, and Tahure; there are 183 communes without a church.