During the disastrous reign of Christopher II (13191332), most of the country was pawned off to the counts (except Skne, 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 Skne and Zealand.
Armed rebellion by Catholic peasants led by Skipper Clement started in northern Jutland. Rebellion swept across Funen, Zealand and Skne. Christian III's army soundly defeated an army of Catholic nobles at Svenstrup on 16 October 1534. Christian forced a truce with the Hanseatic League, which had sent troops to help Count Christopher. Christian III's army, under Johan Rantzau, chased the rebels all the way back to Aalborg and then massacred over two thousand of them inside the city in December 1534.
The Protestants captured Skipper Clement (1534), and later executed him in 1536. Christian III's mercenary troops put an end to Catholic hopes on Zealand and then Funen. Skne rebels went as far as proclaiming Christian II king again. King Gustav Vasa of Sweden sent two separate armies to ravage Halland and Skne into submission. Besiegers finally starved the last hold-outs in the rebellion, Copenhagen and Malm, into surrender in July 1536. By the spring of 1536 Christian III had taken firm control.
Attempts to diversify the economy away from agriculture failed. During this period little industry existed, except for a very small amount in Copenhagen (population: 30,000). In the late 17th century a small amount of industry did develop, catering to the military. Denmark suffered in part because of its lack of natural resources. It had nothing much to export except agricultural products. The Netherlands bought the largest share of Denmark's exports. The landlords, only about 300 in number, nevertheless owned 90% of the land in the country.
Rural administration remained primarily the preserve of the large landholders and of a few law-enforcement officials. In 1733, low crop prices caused the introduction of adscription, an effort by the landlords to obtain cheap labor. The effect of this was to turn the previously free Danish peasantry into serfs. The adscription system tied rural laborers to their place of birth and required them to rent farms on the estates.
As rent, peasants were required to work the landlords' plots and could not negotiate contracts or demand payment for improvements made to the farm. Peasants who refused to rent a farm were subject to six years of military service. Danish agriculture was very inefficient and unproductive as a result, since the peasants had no motivation to perform anything more than the absolute minimum of work. Attempts to sell Danish grain in Norway failed because of its low quality compared to grain from the Baltic.
In the late 18th century, extensive agricultural reforms took place, involving the abolition of the old open-field system and the amalgamation of many smaller farms into larger ones. With the abolition of the adscription system, the military could now only obtain manpower through conscription. These reforms were possible because agricultural prices steadily rose in the second half of the century.
Throughout the 18th century the Danish economy did very well, largely on the basis of expanded agricultural output to meet growing demand across Europe. Danish merchant ships also traded around Europe and the North Atlantic, venturing to new Danish colonies in the Caribbean and North Atlantic.