On 5 March 1454, he married Elizabeth of Brandenburg, the widow of the Duke Joachim II "the Younger" of Pomerania-Stettin and daughter of Margrave John of the Neumark. His second wife was Magdalena of Mecklenburg, the daughter of Henry, Duke of Mecklenburg-Stargard. In 1458, his father died and he and his older brother, Eric II began jointly ruling Pomerania.
She died in early 1465. They had two sons: Swantibor V and Ertmar, both born in 1464, both died of the plague at an early age. This marriage was childless.
After Wartislaw"s death, Magdalena married Count Burkhard of Barby-Mühlingen.
They quickly got into a dispute over the inheritance and succession of Pomerania-Stolp and Pomerania-Rügenwalde. Eric had married princess Sophia, the daughter of Duke Bogislaw IX and after the death in 1459 of Eric of Pomerania, the last duke of Further Pomerania, wanted to rule Further Pomerania alone.
Wartislaw wanted to rule Further Pomerania jointly, while Elector Frederick II of Brandenburg claimed Further Pomerania on behalf of his ward, the minor Otto III of Pomerania-Stettin. In 1464, Otto III died of the plague.
With his death, the Pomerania-Stettin line of the House of Griffins died out.
Frederick II then claimed that Pomerania-Stettin was a completed fief of Brandenburg, and that it should fall back to Brandenburg, while Eric II and Wartislaw X held that Pomerania-Stettin should fall to the surviving line of the House of Griffins. This led to a conflict known as the Stettin War of Succession. Wartislaw X showed himself as an implacable opponent of the Hohenzollerns.
Due to Wartislaw"s intransigence, a compromise with the Hohenzollerns was only possible after his death.
This treaty confirmed an agreement from 1472, that Wartislaw had approved. The key points were that the Dukes in Wolgast were allowed to keep Pomerania-Stettin, but had to accept that they were vassals of Brandenburg and held Pomerania as a fief.
Wartislaw" opposition had been directed mainly against this last provision. After Wartislaw"s death, Bogislaw X reunited all part of Pomerania and ruled the Duchy for almost fifty years.
In the end, he also successfully challenged the status of Pomerania as a fief of Brandenburg.
The issue was finally settled by Bogislaw"s sons George I and Barnim XI in the Treaty of Grimnitz of 1529. Wartislaw X died in 1478 and was buried in the monastery at Neuenkamp, which later evolved into the city of Franzburg.
