Formerly the seat of a diocese. Constance, a very ancient town situated where the River Rhine flows out of the Bodensee (between the Bodensee and the Untersee) in the south-eastern part of the Grand Duchy of Baden, was originally a village of lake-dwellers which under Roman rule was fortified by Constantius Chlorus in 304. Christianity seems to have been introduced into Constance and the neighbouring country by Roman legionaries as early as the end of the second or the beginning of the third century. The episcopal see was first at Vindonissa, the present Windisch in the Canton of Aargau in Switzerland. It is not known when this see was erected. The first bishop of whom history has preserved any record is Bubulcus who was present at the Burgundian Synod of Epaon in 517. (Mansi, Ampl. Coll. Conc., VIII, 565.) He was succeeded by Grammatius, who attended a Frankish synod at Clermont in 535 (ibid., VIII, 863), one at Orléans in 541 (ibid., IX, 120), and a third at Orléans in 549 (ibid., IX, 136). After this time history makes no further mention of the Diocese of Vindonissa. Since, however, the neighbouring city of Constance is for the first time mentioned as an episcopal see about this time, it becomes almost a certainty that from Vindonissa the see was transferred to Constance. The episcopal catalogues of Constance designate Maximus as the first and Rudolph as the second bishop, but nothing further is known about them. Walafrid Strabo, in his "Vita S. Galli", speaks of certain Gaudentius as Bishop of Constance, after whose death (c. 613) the bishopric was offered to St. Gall who, however, refused the dignity and recommended his disciple John in his stead. The sermon which St. Gall preached at John's consecration is still extant (H. Canisius, "Antiquæ Lectiones", edited by Basnage, "Thesaurus monum. eccl. et hist.", Antwerp, 1725, I, 785). Nothing is known of Marcian, Boso, Gangolf, Fidelis, and Rudolph, who are generally designated as successors of John.

The limits of the Diocese of Constance were fixed during the seventh century. The river Iller separated it from the Diocese of Augsburg. From the influx of the Iller into the Danube the boundary turned towards the north-west past Gmünd, across the Neckar, north of Marbach, thence south-westerly till it reached the Rhine south of Breisach (Altbreisach). It followed the Rhine upward to the influx of the Aar, then up this river to the St. Gotthard, whence it turned north-easterly across Canton St. Gall to the source of the Iller. The dioceses surrounding it were Augsburg, Speyer, Strasburg, Basle, Lausanne, Chur, and (since 742) Würzburg. There was not a diocese in Germany which surpassed Constance either in area or population. It belonged to the province of Besançon until it became a suffragan of Mainz in 747. With few changes it retained the above-mentioned dimensions till the time of the Reformation. In the year 1435 the diocese had 17,060 priests, 1760 parishes, and 350 monasteries and convents. During the eighth and ninth centuries the bishops of Constance repeatedly infringed upon the rights of the Abbots of Reichenau and St. Gall and sometimes combined the abbatial with the episcopal dignity. Bishop Sidonius (746-760) was instrumental in the unjust deposition and imprisonment of St. Othmar, the Abbot of St. Gall, in 758 or 759 (Hefele, Conciliengeschichte, III, 596). Most bishops of the tenth century were great and holy men. Solomon III (890-919) had previously (885) been imperial chancellor and was equally beloved as Abbot of Reichenau and St. Gall and as Bishop of Constance. St. Conrad (934-975) was a great friend of the poor, made three pilgrimages to the Holy Land, built three new churches and renovated many old ones. He was canonized in 1123 and became patron of the diocese. St. Gebhard II (979-995) founded the Abbey of Petershausen in 983, began to be honoured as a saint soon after his death, and became patron of the city of Constance. During the conflict between Pope Gregory VII and Emperor Henry IV, concerning the right of investiture, the episcopal See of Constance was occupied by Otto I (1071-1086), who sided with the emperor and was excommunicated because he took part in the deposition of Gregory VII at the Synod of Worms (1076). His successor Gebhard III (1084-1110) was an intrepid defender of the papal rights against Henry V, became Vicar Apostolic for Germany under Urban II (Mansi, Ampl. Coll. Conc., XX, 666 and 715), consecrated the new cathedral at Constance in 1089, held a synod in 1094, at which wholesome ecclesiastical reforms were decreed, and with the consent of the pope freed Henry V from the ban in 1095. During the papal conflicts with the Emperors Frederick I and Frederick II the bishops sided with the emperors until Bishop Henry I, von Thann (1233-1248) returned to papal allegiance in 1246. Bishop Rudolph von Montfort (1322-1334) supported Pope John XXII in his struggle against Louis the Bavarian until 1332, when he joined the party of the emperor. His successor Nicholas, von Kreuzlingen (1334-1344), sided with the popes. While the Council of Constance was in session (1414-1418) the episcopal see of Constance was occupied by Otto III, von Hochberg (1411-1434). From the thirteenth century the bishops of Constance were princes of the German Empire. Their territory, as temporal rulers, extended over twenty-two German (about 482 English) square miles, with a population of about 50,000, and lasted until it was divided between Baden and Switzerland in 1802.

The decline of the diocese begins with the Protestant Reformation. The Swiss Cantons Zurich, Bern, St. Gall, Schaffhausen, and Thurgau were first to adopt the new doctrine (Zwinglianism). They were followed in 1526 by the city of Constance and in 1534 by the Duchy of Würtemberg. Baden became Protestant in 1556, but here the Catholic religion was restored in 1571. The old Faith was also slowly restored in the city of Constance from 1548 when that city came under Austrian rule. From 1526 the bishops of Constance resided at Meersburg. Despite the great losses sustained during the Reformation, the diocese in 1750 still numbered 3774 secular priests, 2764 monks, 3147 nuns, and a Catholic population of 891,948. In 1814 the portion of the diocese situated on Swiss territory was detached and apportioned to the Swiss dioceses of Chur, Basle, and St. Gall. After the death of Bishop Karl Theodor von Dalberg in 1817, the portion of the diocese lying in Würtemberg came under the jurisdiction of the vicar-general of Ellwangen-Rottenburg, and all the Bavarian territory was attached to the Diocese of Augsburg. In 1821 Pope Pius VII dissolved the Diocese of Constance and joined its remaining territory to the newly erected Archdiocese of Freiburg. The most important rulers of the diocese since the Reformation were: Cardinal Marcus Sitticus von Hohenems (Altemps), 1561-1589; Cardinal Andrew of Austria (1589-1600), Jacob Fugger (1604-1626), Karl Theodor von Dalberg (1810-1817) and his Vicar-General Heinrich Ignaz von Wessenberg. The last two espoused the doctrine of Febronius. Dalberg joined the Freemasons and the Illuminati, of whose real tendendcies he was ignorant, and Wessenberg was heart and soul for the anti-ecclesiastical reforms of Emperor Joseph II.

The city of Constance received municipal rights in 780, became a free imperial city in 1192 and was one of the largest and most flourishing cities of Germany during the Middle Ages. Its population is said to have exceeded 40,000. Here the famous Peace of Constance, a treaty between Barbarossa and the Lombard cities was declared in 1183 and an imperial diet was convened by Maximilian I in 1507. Commercially it was highly important on account of its manufacture of choice linen the famous tela di Costanza which was known throughout Europe. Its ecclesiastical renown it owes to the fact that it was the seat of perhaps the largest diocese in Germany and that from 1414-18 the Sixteenth Ecumenical Council was celebrated there. For joining the Smalkaldic League and refusing to accept the Interim of Augsburg in 1548, it was deprived of its privileges as a free and imperial city and given to Austria by Emperor Charles V. It was unsuccessfully besieged by the Swedes in 1633, pillaged by the French (1740-45), and finally joined to Baden in 1805. Its population in 1900 consisted of 15,917 Catholics, 711 Old Catholics, and 565 Jews.

Merck, Chronik des Bisthums Konstanz (Constance, 1627); Neugart, Episcopatus Constantiensis (to 1306), (St. Blasien, 1803 and Freiburg, 1862); Idem, Codex Diplomaticus (St. Blasien, 1791-5); Ladewig, Regesta Episcoporum Constantiensium (in German) von Bubulcus bis Thomas Berlower, 517-1496 (Innsbruck, 1886-90); Ludwig, Die Konstanzer Geschichtsschreibung bis zum 18. Jahrh. (Strasburg, 1894). For the city of Constance: Eiselein, Geschichte und Beschreibung der Stadt Konstanz (Constance 1851); Beyerle, Konstanz im 30-jährigen Krieg (1900); Idem, Grundeigenthumsverhältnisse und Bürgerrecht im mittelalterlichen Konstanz (1900-02).

MICHAEL OTT