From 1520 to 1523, King Gustav I of Sweden led rebel forces within Sweden to unite against the Danish Crown and take back Sweden as independent, during the Swedish War of Liberation. He successfully took back the much of the land, and was elected King in June 1523.
The important city of Stockholm, traditionally the capital of Sweden, was still in Danish hands. Following his election and coronation, he swiftly moved to take it back. Through making of arrangements with foreign traders in the city, the citizens moved to let King Gustav's forces in. Later that month, Stockholm become once more the capital city of Sweden.
The Deceit of Malmö
Over the next year, King Gustav secretly liased with rebel forces in Norway, as many Norwegians resented the dominance of Denmark and the Danish language over what they still saw as their country. Despite being called Denmark-Norway, the so-called Union had a Danish King, was governed from Copenhagen and its only official language was Danish. Thousands of Norwegian men had been raised by the Swedish King for this cause, and he moved several thousand Swedish men to near the Norwegian border in preparation for 24 August 1524.
King Gustav I contacted the Danish crown claiming to want to make some kind of settlement. They planned to meet in Malmö at the end of August 1524, but the Swedes had formulated a plan. Men sent by the Swedish crown impersonating King Gustav (and others impersonating his generals) arrived in Malmö on 24 August 1524, and met with King Frederick of Denmark and his generals and advisors. They all stayed in a fortified Danish royal palace there, and agreed that they were not to be interrupted until an agreement was made or they adjourned/cancelled the meeting themselves.
The real King Gustav and his generals travelled secretly to the Norwegian border, disguised as peasants, where they met with the rest of the Swedish army members who had been moved there. Once word had reached them that King Frederick and the impersonator of King Gustav were inside the palace at Malmö co-ordinating a treaty, the Swedish troops met up with the Norwegian rebels. The underground movement which had been gathering momentum for over a year now came out in the open, and on 26 - 28 August 1524, they drove the Danish out of Norway. Little resistance was met, and no Danish army/navy response could be commanded quickly enough, as the Danish King and his generals were all inside the palace in Malmö.
King Gustav had cleverly insisted that some of his troops were stationed surrounding the palace, so that no news could get in of the invasion. However, when violence started to erupt outside as people tried to get in to bring the message to King Frederick and his men, the noise could be heard from inside the castle. Knowing the meaning of this, the impersonator of King Gustav claimed he 'feared for his personal safety', and said that their agreements would have to be postponed. The representatives of the Swedish crown hastily left before the Danes, and fled the area for Stockholm.
The Scanian War
With the Norwegian state having the backing of Swedish forces, an instant scramble occurred to heavily fortify the ports and coastlines of Southern Norway, making any attempts at direct reoccupation by the Danes effectively impossible. While the furious Danish King tried to plot some kind of retaliation against Sweden, in Late September 1524, Sweden attempted to start to mount an invasion upon the regions of Southern Sweden under Danish control. While the area had quite strong defences, the Danes did have to really put up a fight.
Although the area of land was quite small, the two sides fought for over a year. Denmark showed no signs of giving in, before in October 1525, the Swedes managed to push the Danes back to just the city of Malmö itself. With the Danes not getting anywhere, and simply losing many men to the battle, the Danish Crown offered a conditional surrender to the Kingdom of Sweden on October 15. They said that they would surrender and retreat to Denmark, provided the Swedes promised to never attempt to invade any of the land in the area which has been traditionally referred to as Denmark (i.e. Jutland and the main Danish islands). The Swedish Crown said that it would agree, provided that the Danish Crown agreed the same thing for the Swedish and Norwegian mainlands. They swiftly accepted, and on November 17, The Danish Army withdrew from its last Swedish stronghold in Malmö.
The Beginnings of a "Greater Denmark"
The Danish Crown realised that while the core nation of Denmark was safe from Swedish invasion, the Swedes had formed a large empire that could potentially jeopardise any attempts to expand their territory in any way. As such, Denmark quickly sought to increase its power, influence and territorial extent as soon as possible.
King Christian IV knew that the leaders of the Union of the Duchies of German Nordland felt threatened by the Holy Roman Empire to its south. Despite having left the empire (just over two years before King Frederick made his proposal) without any problems, there was an ever present hostile feeling from these Catholic neighbours. The Danish Crown made contact with the Union of Duchies in December 1526, claiming that if they were to enter into a personal union under his monarchy, they would be in a much stronger political position, and would have more of a defence force available to them. The dukes of German Nordland deliberated over this, and decided to agree to his terms.
With this, the Empire of Denmark-Nordland was formed.
The Debate over Iceland and the Faroes
Before the Swedish Liberation of Norway, there were several overseas possessions which had been directly administered by Denmark-Norway. Both Iceland and the Faroe Islands had been under Norwegian control before the time of the Kalmar Union, so when Sweden left and only Denmark-Norway remained they stayed a part of the union. This, however, left a problem following the Liberation of Norway.
In August 1527, Denmark-Nordland officially claimed both the Faroe Islands and Iceland as its own territories. Whilst this was not a completely surprising action (as since the breakdown of Denamrk-Norway 2 years prior, the Danish Crown had been unofficially administrating them), several weeks later the Swedish government issued a declaration to Denmark-Nordland stating this:
"Before Norway entered the Kalmar Union, her possessions included the Faroes and Iceland. Sweden subsequently broke away from the Union, leaving Denmark-Norway, a union of the two states left. This was a descendant of the Kalmar Union, so when Norway left to join Sweden, she retained to the possessions she originally entered the Union with.
As such, the Royal House of the Greater Kingdom of Sweden hereby claims the territories known as the Faroe Islands, and the greater island of Iceland as its own possessions."
King Frederick of Denmark initially refused to make a statement, and simply ignored the Swedish claims to those lands. He had no real concern, as he had control over the Faroe Islands and Iceland anyway, so presumed that all would remain fine.
The Kirkjubøur Ransom
After half a year of no reaction from the Danish Government to Sweden's position statement on the Faroe Islands and Iceland, the Swedish Navy initiated something that King Frederick I was most certainly not expecting.
On 17 April 1527, several hundred men of the Swedish Navy sailed to the Faroe Islands and held hostage the small town of Kirkjubøur. It was not huge, but it was a particularly important place within the area, as it contained the cathedral for the Diocese of the Faroe Islands. The townspeople were held there by force by the Navy men, and the same day, the following statement was issued to the Danish Government:
"The Royal House of the Greater Kingdom of Sweden has officially taken up control of the Faroese town of Kirkjubøur. We expect that you will recognise our sovereignty, for the sake of the Faroese people. If you do so, and wish to retain the Faroe Islands, you may purchase them from us at the cost of 250kg of gold.
If you do not do so by 20 April, we shall continue our advance through the islands, and shall not necessarily be so kind their inhabitants."
In the evening of 19 April, several Danish naval ships arrived near Kirkjubøur. In the early morning of 20 April, the ships' men went ashore armed, ready to take back the town. The defiant Danish Crown had, however, completely underestimated the number of Swedes there. The Danes were defeated easily, with all but a few (who escaped in small boats) massacred by the Swedish navy men holding the town.
In response to the evident refusal by Denmark-Nordland, the Swedish Navy advanced through the islands with little resistance, though those Faroe Islanders who tried to put up a fight were quickly killed.
On 23 April, the Swedish Crown issued yet another statement:
"In order to prevent any more unnecessary suffering on the part of the Faroe Islanders, and to guarantee the safe return of the Islands to the control of Denmark-Nordland, the Royal House of the Greater Kingdom of Sweden hereby strongly recommends that the previously suggested amount is paid in due course.
Additionally, at the discretion of the Danish Crown, a sum double that required for the Faroe Islands may also be paid in order to ensure the transferral of Iceland.
Please take action promptly."
Subsequently fearing a further, more violent course of action on the part of Sweden, the Denmark-Nordland government agreed to these terms. They arranged for a Swedish naval ship to pick up 750kg of gold from the port at Copenhagen, as they wanted to secure Iceland for themselves as well. The Icelandic people had heard of this statement, and feared that what had happened to the Faroese might be brought upon them, too.
On 1 May 1527, the Swedish Crown officially recognised the Faroe Islands and Iceland as territories of Denmark-Nordland.
Shetland and Orkney
Back in 1468, the Norwegian King Christian I pawned Orkney to the Kingdom of Scotland, as the Norwegian Crown was, at the time, struggling to pay the dowry for his daughters marriage to King James III. On 28 May of the next year, 1469, he also pawned Shetland. It became evident after several years that Norway was not going to pay the dowry sum, so Shetland and Orkney were annexed to the Kingdom of Scotland.
In February 1528, the Swedish Crown purchased these islands back from Scotland, for an unknown sum. There were still many ethnic Norwegians residing in the islands, so it provided a way of both accommodating their needs and showing off the extent of Swedish territory to Denmark-Nordland.