King Christian 1. & queen Dorothea Painting Frederiksborg Castle Hillerød, Denmark

The Kalmar union - the nordic union from Christopher of Bavaria's reign – had disintegrated for if there was something the Danes didn't want it was to have a Swedish king. Denmark was more interested in re-uniting South Jutland with the kingdom. By considering Adolf 8., the duke of Schleswig-Holstein, as king, the prospect was to tie not only South Jutland but all of Schleswig-Holstein to the kingdom – but the 47 year old thought he was too old and appointed his nephew, the young count Christian of Oldenburg.

After duke Adolf made Christian promise never to unite Denmark and South Jutland under one sovereign and the national council arranged for Christopher's 18 year old widow, Dorothea of Brandenburg, to get married to Christian of Oldenburg, who was only four years her senior, he could be made king.

Christian 1. was elected in Viborg national assembly on 28th September 1448 and the year after he and queen dowager Dorothea got crowned in Frue Church in Copenhagen. At a major Danish-Swedish national assembly in Halmstad in 1450 about re-establishing the Union Christian 1. accepted the conditions the nobility made. The agreement was that Karl Knutsson remained king of Sweden but had to give up Norway. Christian 1. was to be king of Denmark and Norway and whoever lived the longest of the two kings was to inherit the others kingdom. Karl Knutsson took revenge by letting his troops pillage Scania, but in 1457 the tax-burdened Swedish farmers and the Swedish national assembly had had enough. King Karl was dethroned and had to flee to Gdansk and Christian 1. was made king in the re-established Union.

King Christian 1. Andrea Mantegna Image collection of the Royal Art Academy, Copenhagen

In 1464 there was another uprising in Sweden. This time Christian I was de-throned. The exiled Karl Knutsson wasted no time and returned to the Swedish throne in 1467. All domestic problems with the high nobility expressed themselves in the king directing severe blows against nobility. The powerful Thott noble family had their estates confiscated when the Gothlandic and Scanian parts of the family allied themselves with the Swedes. The confiscations rectified some of Christian 1.s ailing finances and helped consolidate the Crown.

As a result of these events Christian 1. called the first assembly of the estates of the realm in 1468 in Danish history.

Karl Knutsson died in 1470 and Christian 1. immediately saw an opportunity for once again becoming the king of Sweden. The year after he managed to put together a fleet of 70 ships, despite his ailing finances, and sailed towards Stockholm with 3,000 men. In the battle of Brunkeberg outside Stockholm on October 10 he suffered a crushing defeat and only just managed to avoid being killed himself. In the peace talks that followed it was decided to find a way to reinstate Christian 1. as king of Sweden by arbitration. This never happened – instead the Swedish national assembly elected Sten Sture as regent.

In an attempt to further undermine the power of the nobility Christian 1. travelled to Rome in 1474, where he made an arrangement with the Pope which gave him the right to fill the highest church posts in Denmark and Sweden as well as open a university in Copenhagen. He later also managed to get Holstein's nobility under control and to be released from most of the debts he had to the duchies, so towards the end of his reign the Crown was relatively strong.

Christian 1. died in 1481 and was buried in Roskilde cathedral. He was succeeded by his son, Hans.