Wartislaw III, Duke of Pomerania

Wartislaw III (c. 1210 – 17 May 1264) was a Griffin duke of Pomerania-Demmin. Son of Casimir II of Pomerania-Demmin and Ingardis of Denmark, he was married to a Sophia of an unknown house. As he did not have any children, Pomerania-Demmin ceased to exist with his death.

Ingardis ruled Pomerania-Demmin in place of young Wartislaw from Casimir's death 1219 until 1226. At that time, Pomerania-Demmin as well as the other part duchy Pomerania-Stettin were under Danish overlordship, which diminished after the 1227 Battle of Bornhöved and was finally dismissed when Wartislaw successfully countered a Danish expedition in 1234 with his Lübeck allies.

1236 was a harsh year for Pomerania-Demmin, as Wartislaw lost a great part of his possessions to his rivaling neighbors Mecklenburg and the Margraviate of Brandenburg. First, a Mecklenburgian expedition led by Henry Borwin III of Mecklenburg-Rostock annexed most of Circipania, the western part of the duchy comprising the terrae Gnoien, Altkalen and Demmin, leaving only the residential burgh of Demmin under Wartislaw's control. Also, Wartislaw had to recognize Brandenburg's overlordship over the remainder of his duchy in the 1236 Treaty of Kremmen. In the same treaty, he ceded the terrae Stargard, Wustrow and Beseritz to Brandenburg, which soon after were taken over by Mecklenburg and became known as Mecklenburg-Strelitz.

Yet, in the North, Wartislaw was able to expand his sphere of influence up to the Ryck river into the territory of Hilda, now Eldena abbey set up there by the princes of Rügen. Wartislaw involved into developing Eldena's market and saline settlement Greifswald by granting it market rights together with the Rugian prince and received the town as a thief from Eldena in 1248.

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