The most famous line of the proclamation was that the Danish Duchy of Schleswig and the County of Holstein within the Holy Roman Empire, should now be, in the original Middle Low German language, Up Ewig Ungedeelt, or "Forever Undivided".
Another clause granted the nobility the right to revolt should the king break the agreement (a common feature of several medieval coronation charters).
The process was greatly accelerated following the Lutheran Reformation, which introduced German liturgy in the churches in southern Schleswig - although the vernacular in most of this area was Danish.
In fact, many historians have seen the construction of the first border fortifications, known as the Danevirke, as the first proof of the beginning of an independent Danish state.
The border was challenged from both sides; Charlemagne sought to conquer Denmark, and Danish kings supported Saxons wishing to cast off the Frankish rule.
1214 marked an important step in this process, when the Holy Roman Emperor Frederick II issued a Golden Bull surrendering all imperial territories north of the rivers Elbe and Elde to Valdemar the Victorious.
Their united forces formed a very respectable array, and they took and destroyed a number of towns, and had recovered a great part of the County of Holstein, when they were opposed by Schauenburg Count Adolf IV of Holstein, who had been joined by his liege lord Albert I, Duke of Saxony and Prince-Archbishop Gerhard II of Bremen.
These local lords sought to keep Schleswig independent of the king and to forge close ties to Holstein within the Holy Roman Empire.
The bankruptcy of Denmark resulted in a rising influence of the King's creditors (mostly Holsatian nobles) in all parts of the country.
Schleswig was consequently granted as a fief to Count Gerhard III of Holstein-Rendsburg, the leader of one of the then four Holstein lines of the Schauenburg dynasty.
King Christopher was only left in effective control of the island of Langeland and was faced with an impossible task of raising 100,000 silver marks to redeem his country.
In 1374, Valdemar succeeded in buying large tracts of land in the province and was on the verge of starting a campaign to conquer the rest when he died on 24 October 1374.
In 1409, Margaret's adopted son and Denmark's future king, Eric of Pomerania forced the Schauenburgers to surrender the city of Flensburg to him.
In 1411, Holstein-Rendsburg, which until 1403 had incorporated all Schauenburg lines except of Pinneberg, retook Flensburg, but in 1412 both sides agreed that an arbiter should settle the dispute, Ulrich I, Duke of Mecklenburg-Stargard.
The Assemblies of both Lund, Ringsted, and Ribe all reached the conclusion that Schleswig was governed by Danish laws and formed part of Denmark.
The assembly ruled that Schleswig was part of Denmark with the following argument ... the (people) of Southern Jutland use Danish law and have kept it since it was given.
Thirdly, every man knows where the borders are located, that Denmark and Holstein are separated; even the language in Southern Jutland is Danish to this day.
Henry IV, Count of Holstein-Rendsburg and Duke of Schleswig, strongly protested this verdict and refused to follow it.
Christopher of Bavaria) acquired the loyalty of Count Adolf VIII of Holstein-Rendsburg by granting him the entire Duchy of Schleswig as a hereditary fief but under the Danish crown.
In 1459, Adolf died without leaving an heir and no other count could produce claims to both the Duchy of Schleswig and the County of Holstein-Rendsburg.
On 5 March, Christian granted a coronation charter (or Freiheitsbrief) which repeated that Schleswig and Holstein must remain united dat se bliven ewich tosamende ungedelt.