History of Denmark between 1036 - 1396
England broke away from Danish control in 1035 and Denmark fell into disarray for some time. Sweyn Estridsen's son, Canute IV, raided England for the last time in 1085. Canute's nephew Sweyn Estridson (1020–74) re-established strong royal Danish authority and built a good relationship with Archbishop Adalbert of Hamburg-Bremen — at that time the Archbishop of all of Scandinavia.
In the early 12th century Denmark became the seat of an independent church province of Scandinavia. Not long after that, Sweden and Norway established their own archbishoprics, free of Danish control. The mid-12th century proved a difficult time for the kingdom of Denmark. Violent civil wars rocked the land. Eventually, Valdemar the Great (1131–82), gained control of the kingdom, stabilizing it and reorganizing the administration. King Valdemar and Absalon (ca 1128–1201), the bishop of Roskilde, rebuilt the country.
During Valdemar's reign construction began of a castle in the village of Havn, leading eventually to the foundation of Copenhagen, the modern capital of Denmark. Valdemar and Absalon built Denmark into a major power in the Baltic Sea, a power which later competed with the Hanseatic League, the counts of Holstein, and the Teutonic Knights for trade, territory, and influence throughout the Baltic. In 1168, Valdemar and Absalon gained a foothold on the southern shore of the Baltic, when they subdued the Principality of Rügen.
In the 1180s, Mecklenburg and the Duchy of Pomerania came under Danish control. The Danes however lost most of their southern gains after the Battle of Bornhöved (1227), but the Rugian principality stayed with Denmark until 1325.
In 1202, Valdemar II became king and launched various "crusades" to claim territories, notably modern Estonia. Legend has it that the Danish flag, the Dannebrog fell from the sky during the Battle of Lyndanisse in Estonia in 1219. A series of Danish defeats culminating in the Battle of Bornhöved on 22 July 1227 cemented the loss of Denmark's north German territories. Valdemar himself was saved only by the courageous actions of a German knight who carried Valdemar to safety on his horse.
From that time on Valdemar focused his efforts on domestic affairs. One of the changes he instituted was the feudal system where he gave properties to men with the understanding that they owed him service. This increased the power of the noble families and gave rise to the lesser nobles who controlled most of Denmark. Free peasants lost the traditional rights and privileges they had enjoyed since Viking times.
By the late 13th century, royal power had waned, and the nobility forced the king to grant a charter, considered Denmark's first constitution. Following the Battle of Bornhöved in 1227, a weakened Denmark provided windows of opportunity to both the Hanseatic League and the Counts of Holstein. The Holstein Counts gained control of large portions of Denmark because the king would grant them fiefs in exchange for money to finance royal operations.
Valdemar spent the remainder of his life putting together a code of laws for Jutland, Zealand and Skåne. These codes were used as Denmark's legal code until 1683. This was a significant change from the local law making at the regional assemblies had been the long-standing tradition. Several methods of determining guilt or innocence were outlawed including trial by ordeal and trial by combat. The Code of Jutland was approved at meeting of the nobility at Vordingborg in 1241 just prior to Valdemar's death. Because of his position as "the king of Dannebrog" and as a legislator, Valdemar enjoys a central position in Danish history. To posterity the civil wars and dissolution that followed his death made him appear to be the last king of a golden age.
The Middle Ages saw a period of close cooperation between the Crown and the Roman Catholic Church. Thousands of church buildings sprang up throughout the country during this time. The economy expanded during the 12th century, based mostly on the lucrative herring-trade, but the 13th century turned into a period of difficulty and saw the temporary collapse of royal authority.
During the disastrous reign of Christopher II (1319–1332), most of the country was pawned off to the counts (except Scania, which went to Sweden) after peasant revolts and conflicts with the Church. For eight years after Christopher's death, Denmark had no king, and was instead controlled by the counts. After one of them was assassinated in 1340, Christopher's son Valdemar was chosen as king, and gradually began to recover the pawned territories, which was completed in 1360.
The Black Death, which came to Denmark during these years, also aided Valdemar's campaign. His continued efforts to expand the kingdom after 1360 brought him into open conflict with the Hanseatic League. He conquered Gotland, much to the displeasure of the League, which lost Visby, an important trading town located there.
The Hanseatic alliance with Sweden to attack Denmark initially proved a fiasco since Danish forces captured a large Hanseatic fleet, and ransomed it back for an enormous sum. Luckily for the League, the Jutland nobles revolted against the heavy taxes levied to fight the expansionist war in the Baltic; the two forces worked against the king, forcing him into exile in 1370. For several years, the Hanseatic League controlled the fortresses on "the sound" between Scania and Zealand.
The Petersberg Citadel is one of the largest extant early-modern citadels in Europe and covers the whole north-western part of the Erfurt city centre. It was built after 1665 on Petersberg hill and was in military use until 1963. It dates from a time when Erfurt was ruled by the Electors of Mainz and is a unique example of the European style of fortress construction. Beneath the citadel is an underground maze of passageways that can be visited on guided tours organised by Erfurt Tourist Office.
The citadel was originally built on the site of a medieval Benedictine Monastery and the earliest parts of the complex date from the 12th century. Erfurt has also been ruled by Sweden, Prussia, Napoleon, the German Empire, the Nazis, and post-World War II Soviet occupying forces, and it was part of the German Democratic Republic (East Germany). All of these regimes used Petersberg Citadel and had an influence on its development. The baroque fortress was in military use until 1963. Since German reunification in 1990, the citadel has undergone significant restoration and it is now open to the public as a historic site.