In 1209, the Dukes of Pomerania started another war against Jaromar I and the city of Stralsund that was flourishing under his protection.

Margrave Otto II defeated the Danish army under Peter of Roskilde and occupied Pomerania.

Denmark reached the peak of its power and Valdemar ruled as King of the Danes, Slavs, Jutes and Nordalbingians.

In 1214 in Metz, Frederick II enfeoffed Valdemar with all German and Slavic territories north of the Elbe and Elde rivers, and this enfeoffment was confirmed by the Pope.

Sovereignty of the Dukes over Gützkow and Demmin was secured and the economy and culture were stimulated by the immigration of German settlers and by the monastery Jaromar I had founded at Eldena.

In 1218, the frail bishop Sigwin of Cammin died and was succeeded by his provost, the more vigorous Conrad II.