Valdemar II King-Archbishop of Bremen-Denmark

No not the Valdemar II I take my name after but his fathers cousin. Valdemar Knudsen was bastard son of Canute V of Denmark, Prince-Archbishop of Bremen and regent for OTL Valdemar (Valdemarsen) II (in his position as Duke of South Jylland*) while he was child. Valedemar Knudsen tried to overthrow Valdemar Valdemarsen older brother King Canute (Valdemarsen) VI of Denmark, through in truth to take power himself. Unlucky for him he ended up imprisoned and was forcved to swear peace, so what if we change this a little. We kill of Canute Valdemarsen while his brother are still a child around 1184, leaving Valdemar Knudsens as the closest adult heir, while he's a bastard, he could call on the presence of Sven Tveskæg, whom was also believed to be bastard. So Valdemar Knudsen end up King of Denmark and Prince-Archbishop of Bremen. In OTL he lived to 1235-1236 which would give him 50 year of rule

How would this develop? Would Denmark end up a permanent part of Prince-Archbishopric of Bremen. So we would get a King-Archbishopric of Bremen-Denmark. While the royal family was delegated to Dukes of Schleswig swearing fealthy to the King-Archbishop (maybe with second sons or cousins being gromed to become King-Archbishops).

I find it unlikely, likely when Valdemar Knudsen dies the Kingdom will return to secular member of the family. But the idea are so neat that it would be more interesting to look what would happen to the new ecclessial state. It importance would be enourmous among Catholics it would be second to the pope thank to it enourmous secular power. For the Hanse it's a disaster, because it would both border the important Hanse city Lübeck, Hamburg and Bremen and would maybe even succed in stopping the raising of Hamburg and Bremen to imperial cities (which would mean that they stayed part of Bremen). With control over Denmark Bremen would likely take part in the Baltic crusades as Denmark did. Whether it would have more succes are the question.

Interesting idea, insanity or interesting insanity?

*Schleswig

Not to throw a spanner in the works but you know that the illegitimate son of Erik 3 "Lam/Spage" - Magnus - might have been alive at the death of Valdemar I.
If Valdemar I doesn't have any male issue Magnus would certainly be seen by Valdemar I as a possible contender to the throne. The other would be Valdemar Knudson.
That would make for another pretender to the Kingdom and this one would not tie it to the clerical see of Bremen and make possible a new royal line.
This game of succession would probably be carried on by the next King Cnut the VI who didn't have any male issue.

If Valdemar Knudson is the only other living male pretender to the throne he might not be thrown away as a bishop. Most probably he would be groomed to compete for the throne.

The only legitimate pretender would only be born 1216 - Erik Erikson of Erik Knutson of Sweden and Rikissa Valdemars of Denmark.

So truly I don't see Valdemar Knudson become Bishop of Bremen; he would likely keep the seat as Duke of Slesvig and Magnus eventually get another Duchy: Halland or Blekinga. And we would see another civil war when Cnut VI dies in 1202 with no legitimate heir between the parties of Magnus Erikson and Valdemar Knudson with Erik Knutson of Sweden on the sideline waiting to grab the spoils for his son to be.