Schleswig, formerly a duchy and diocese of northwestern Germany, now a part of the Prussian Province of Schleswig-Holstein. In the early Middle Ages the southern part of the peninsula of Jutland was a bone of contention between the Germans and the Danes. When in the fifth century the greater part of the Germanic population had left the region in order to seek a new home in Britain, the Danes or Jutes pushed their way into the country and the part of the Germanic population that had remained behind amalgamated with the new masters. The Frisians were the only ones to retain their national peculiarities after losing their national independence. About the beginning of the ninth century Charlemagne conquered the southernmost part of the peninsula; he formed the territory on the Eider into a Mark as a protection against the Slavs. As early as his reign Christian missions began to gain a foothold in the region. The first preacher of the Christian faith was the priest Atrebanus, who was a pupil of Willehad, the first Bishop of Bremen. Atrebanus founded a mission station among the heathen Dithmarschians, but suffered the death of a martyr during the Saxon revolt in 780. During the reign of Louis the Pious, Archbishop Ebo of Reims, the emperor’s confidential friend, reestablished the mission, but without great success. About 850 Ebo’s companion, Ansgar the Apostle of the North, erected the first church in the little town of Schleswig; this was soon followed in 860 by the building of the church at Ripen. These successes of the mission of the Carlovingian period were destroyed during the heathen reaction that followed. Under the vigorous administration of the German king, Henry I, the Mark on the Eider was reestablished in 934, and soon after this Unni, Archbishop of Ham-burg, once more took in hand the bringing of the north to Christianity. Christian communities increased, especially after the Danish King Harold Blue Tooth (d. 986) had accepted Christianity, and the three dioceses of Schleswig, Ripen, and Aarhaus were founded at the request of Archbishop Adaldag of Bremen. These dioceses were made suffragans of Bremen. The first Bishop of Schleswig was Hored, who was present in 948 at the German synod of Ingelheim. The Diocese of Schleswig, though, did not include the whole of the later Duchy of Schleswig, as the northwestern part belonged to the Diocese of Ripen, and the Islands of Alsen, Aro, and Fehmarn to the Diocese of Fiinen.
During the reign of King Harold Blue Tooth, Christianity became the dominating religion of Denmark and Schleswig. Paganism, however, regained the supremacy when Harold’s son Sven with the Forked Beard, who had been a viking, returned home in 985 and overthrew his father. Christians were ill-treated, the Diocese of Aarhaus was suppressed, and the two other bishops were driven away. Yet in the last years of his life Sven with the Forked Beard turned to Christianity, and his son Canute the Great, who by the conquest of England created a great northern empire, established Christianity at last in his territories. In 1035 his son-in-law the German King Conrad II gave him the Mark of Schleswig as compensation for the alliance he had maintained with Germany for many years. The Mark included the territory between the Eider, Schlei, and Treene. The political separation from the German Empire was soon followed by the ecclesiastical. Canute had reorganized the Danish Church and had divided it into nine dioceses. In 1103 or 1104 a separate Danish archdiocese was erected at Lund for all these bishoprics, and, notwithstanding the protests of the Archbishop of Bremen, Schleswig was made a suffragan of Lund. Before long the political union with Denmark was weakened again. From the time that the whole of Schleswig belonged to Denmark it was ruled by royal governors; these governors were generally princes of the royal house who grew steadily more independent of the king. In 1115 Knut Laward was able to gain the viceregency of Schleswig in fief from the Danish King Niels, and was also made duke of this territory. Thus a basis was laid for a more independent position of the province within the Kingdom of Denmark. Under Knut’s successors Schleswig was often united with Denmark, as Waldemar I and II; dukes of Schleswig, were also kings of Denmark. These kings, however, sought to keep Schleswig as their personal domain, separate from the administration of Denmark. In 1231 Abel, the youngest son of Waldemar II, was granted the duchy; he founded an independent ducal line that ruled the duchy for over a hundred and fifty years.
Both politically and ecclesiastically the two centuries following the reign of Knut Laward form the most prosperous period of the province. Of the bishops, Alberus (1096-1134), in particular, was very active in his office, and labored among the Frisians who had been conquered by Knut. The diocese received large grants of land from Waldemar I, possessions that were scattered through all parts of the duchy; in 1187 the diocese was released from all payment of imposts and taxes to the king. A number of monasteries arose that did much for the intellectual and material development of the country; nearly thirty monasteries can be proved to have existed in the period before the Reformation. The most important of these were the Cistercian abbeys of Lugumkloster, Guldhom, and Schleswig, the convent of St. John for Benedictine nuns at Schleswig, the Franciscan monasteries at Hadersleben, Tondern, and Schleswig, and the Dominican monastery at Schleswig. In the course of time many of these monasteries had obtained large landed possessions. When in 1325 Duke Eric II died and left a minor son Waldemar V, King Christopher II of Denmark wished to become the guardian and thus gain control of the duchy. However, the powerful Count Gerhard III of Holstein of the Schauenburg line, who was an uncle of Waldemar, and also the latter’s guardian, opposed the king. Gerhard gained control of the government, and drove Christopher out of his own kingdom. Waldemar V was elected King of Denmark and in return gave the Duchy of Schleswig to his uncle, the Count of Holstein. Thus the duchies Schleswig and Holstein became united at the same time (1326) Waldemar made a law, called the “Constitutio Waldemariana”, by which in future the same person could never be the ruler both of Denmark and Schleswig. During the troubles caused by the return of the banished King Christopher the Counts of Holstein were not able to maintain their control of the Duchy of Schleswig. It was not until the era of Gerhard VI, the grandson of Gerhard III (assassinated 1340), that the counts of Holstein regained possession of Schleswig; Gerhard VI was granted the duchy in fief by Queen Margaret of Denmark, and in 1403 gained possession of almost the whole of the duchy of Holstein on account of the extinction of the line of Kiel. Since this time Schleswig has always been united with Holstein which was a state of the German Empire.
On the death in 1459 of Adolf VII, son of Gerhard VI, the line of the counts of Schauenburg became extinct, and the estates of Schleswig and of Holstein elected in 1460 as duke and count the Danish King Christian of the Oldenburg dynasty, who was the son of Adolf’s sister. The new duke and count, though, was obliged to swear that both countries should be “forever undivided”, and that they should be independent of Denmark in their internal administration and constitution. Thus both territories were united by personal union with Denmark, the Duchy of Schleswig (which had been a Danish fief), and the Countship of Holstein, which in 1474 was also raised to a duchy by the Emperor Frederick III. In spite of this union with Denmark both territories remained German in character; the language of the courts and official documents was German, the law of the cities was German, the nobility was German, the bishop and chapter of the Diocese of Schleswig were chosen from German families. The close intellectual union with Germany was still further promoted by the Reformation, which in Schleswig as in the whole of Denmark was largely the work of the rulers. The Bishop of Schleswig of that period, Gottschalk of Ahlefeld (1527-41), fearlessly opposed, indeed, the intrusion of the new doctrine, but his efforts had little success. For in the course of the fourteenth and fifteenth centuries, especially during the rule of the counts of Holstein, the bishops had ceased to be independent of the dukes; from vassals of the king they had become vassals of the dukes and had sunk into mere local bishops. In 1536 Lutheranism was declared the religion of the state by Christian III, the exercise of the Catholic faith was forbidden, and the property of the diocese was confiscated. After Gottschalk’s death Tileman of Hussen was appointed in 1541 the first Lutheran Bishop of Schleswig. He was followed by four other Lutheran bishops, after which the diocese was suppressed in 1624. While the Catholic Church was entirely suppressed in Schleswig, in Holstein a few Catholic communities were permitted to remain in existence. In the seventeenth century Catholic Church services were allowed to be held again in a few places. In 1667 all these Catholic communities were placed under the care of the newly-established Vicariate Apostolic of the Northern Missions, and shared its vicissitudes.
In 1544 the two duchies were divided between the three sons of the king and Duke Frederick I (d. 1533). The basis of the division was this: three equal portions were formed for the three brothers out of the duchies, which portions were named after the castles of Sonderburg, Gottorp, and Hadersleben, while the courts, the system of taxation, the army, and the diets that were held at Flensburg for Schleswig, and at Kiel for Holstein, remained in common. When in 1580 the Hadersleben line became extinct, another division was made, the possessions of the Hadersleben line being divided between King Frederick II and Duke Adolf of Holstein-Gottorp (1581). After this there were two lines: the royal, which was called Schleswig-Holstein-Gluckstadt after the seat of administration for the duchies, and from which in the course of time several branches sprang; second, a ducal line called the Gottorp line which, besides sharing in the two duchies, also owned the former Diocese of Lubeck. Duke Frederick III of Gottorp, who ruled from 1616 to 1659, put an end to the subdivisions of the Gottorp line by introducing primogeniture. During the eighteenth century the two ruling dynasties were generally hostile to each other because the Gottorp line sought alliance with Sweden, the enemy of Denmark. Thus the duchies became involved in the Thirty Years’ War and the two wars of the North. In the Treaty of Roeskilde that closed the first war of the North, the Gottorp dynasty received, through the intervention of Sweden, full sovereignty by the suppression of Denmark‘s suzerainty over its share of the duchies. However, in the Treaty of Stockholm that in 1720 closed the second war of the North, which had not been fortunate for Sweden, the Gottorp line was obliged to concede its share of Schleswig to Denmark and only retained its possessions in Holstein. The whole of Schleswig was now obliged to recognize the Danish king as its ruler. In the treaties of 1767 and 1773 the Gottorp dynasty, which had gained the throne of Russia in the person of Peter III, was obliged to renounce its possessions in Holstein also, in return for which it received Oldenburg. In this way Denmark became the sole ruler of Schleswig-Holstein.
The union of the two duchies with the German Empire grew continually weaker, especially as after the dissolution of the German Empire in 1806 the duchies had no protection against the policy of their ruler; this policy, which was to stamp a Danish character upon them, was not affected by the fact that the Congress of Vienna made Holstein a part of the German Empire. The Danes showed plainly more and more their determination to separate the two duchies, which by right should never have been divided, and to gain at least Schleswig as a part of the Danish nation, because the population of Schleswig was largely Danish in speech. The people, however, accepted all the measures of the Danish government very composedly, as the male line of the royal dynasty would soon be extinct and the female line was, by the Salic law of succession, not capable of succeeding in the duchies, although it could in Denmark. The duchies were satisfied even with the constitution granted in 1834, although it was not one in common for both duchies and did not preserve any essential right of the people. King Christian, however, in 1846 published a letter in which he declared the Danish right of succession to be also valid in the duchies, and his successor Frederick VIII (1848-63) was forced by popular assemblies at Copenhagen, soon after he came to the throne, to promise the incorporation of Schleswig into the Danish kingdom. These two events were followed by a revolt of the people of the duchies. On March 24, 1848, a temporary provincial government was established at Kiel, which declared that it assumed for the time being in the name of the ruler, the Danish king, the maintenance of the rights of both duchies, as the ruler had been forced by mob-rule to take a hostile position to the duchies. When, upon this, Denmark sent troops into Schleswig-Holstein, not only did the population of the duchies take up arms, but there was also a great national movement in Germany in favor of their endangered countrymen in the North. Volunteers from all parts of Germany went to the aid of the people of Schleswig-Holstein. King Frederick William IV of Prussia sent an army into the duchies and even the Diet of the German Confederation was carried away by the national enthusiasm. It proclaimed that Schleswig was made a member of the German Confederation and gave to Prussia the direction of the war against Denmark. The Prussian troops and those of the confederation won, it is true, several brilliant victories, especially the carrying of the fortifications of Duppel. However, the lack of a German fleet, and the threatened interference of Russia and Great Britain led Prussia to consent to a truce, which was followed by a treaty in 1850 that was also accepted by the German Confederation. Contrary to the general promise that the rights of the duchies should be respected, they were again given to Denmark. After this the five Great Powers declared at a conference held at London in 1852, that the Danish Kingdom was indivisible in all its parts, that the separate position of the duchies should be maintained within this kingdom, and that should the male line of the Danish dynasty become extinct the succession was to fall to the House of Glucksburg. In this way the right of succession previously valid in the duchies of the Elbe was thrown aside, and the Augustenburg line, that had branched off from the Danish royal house in the sixteenth century, was excluded from the succession to Schleswig Holstein. Consequently the German Confederation and Frederick, Crown prince of Augustenburg, protested against the London protocol, while Prussia and Austria recognized it.
After the duchies were handed over to Denmark there was an energetic attempt, especially in Schleswig, to make these provinces entirely Danish in character. All connection with Holstein was set aside, a custom-house was erected on the Eider, Danish preachers, teachers, and troops were sent into Schleswig, while the German soldiers and officers were brought into Danish garrisons, and lastly Danish was made the language of the Church and schools. When the male line of the Danish royal family became extinct at the death of Frederick VII (November 15, 1863), according to the regulations of the London protocol Christian of Glucksburg succeeded as Christian IX. Immediately after his accession Christian announced a constitution which included the unconditional incorporation of Schleswig into Denmark. The proclamation of this Constitution of November was followed in Germany by unprecendented excitement and manifestations of disapproval, and the demand was made for the complete separation of the duchies from Denmark. Holstein was occupied by the troops of the German Confederation; even Prussia and Austria now took the part of the duchies. These powers called upon Denmark to withdraw the Constitution of November, and when these demands were rejected they sent Prussian and Austrian troops under the command of the Prussian Field Marshal Wrangel into Schleswig in February, 1864. After the fortifications of Duppel, the Island of Alsen, and the entire peninsula of Jutland had been gained by the Germans the Danes saw themselves compelled to yield. In the Peace of Vienna (October, 1864) King Christian renounced all rights over Schleswig and Holstein in favor of the Emperor of Austria and the King of Prussia, and recognized in advance whatever disposition the two monarchs should make of these provinces. The possession in common of the duchies only increased the strain of the relations existing between Prussia and Austria. Austria desired to form a new state of the German Confederation under the government of the Duke of Augustenburg, while Prussia, on the contrary, preferred to keep the region for itself and only permit the country to have a ruler of its own if all traffic, all customs, and the army of the new state were under the control of Prussia. The Prince of Augustenburg would not consent to such an arrangement. In the Treaty of Gastein of August 14, 1865, the duchies were divided between the two powers. Austria took in charge the administration of Holstein, Prussia that of Schleswig. It was seen from the start that this solution of the question could not be of long duration. The tension between the two powers for pre-eminence in Germany led in the next year to a war between them. Austria was defeated, was obliged to withdraw from the German Confederation and to renounce all rights to Schleswig and Holstein in favor of Prussia. From 1867 the two duchies have formed the Prussian province of Schleswig-Holstein (see Vicariate Apostolic of Northern Germany).