Which Pomeranian duke signed the 1630 Treaty of Stettin with Sweden?

The Pomeranian duke who signed the 1630 Treaty of Stettin with Sweden was Bogislaw XIV. As the last reigning duke of Pomerania, he concluded the alliance that allowed Swedish forces to establish themselves in the duchy during the Thirty Years' War.

The agreement was made on 25 August 1630 under the Julian calendar, equivalent to 4 September in the Gregorian calendar. Sweden assumed military control of Pomerania, using its ports and territory as a bridgehead for operations farther into the Holy Roman Empire. The treaty followed Gustavus Adolphus's landing on Usedom earlier that summer.

Bogislaw XIV presented the alliance as a defensive necessity. He argued that Imperial troops had ravaged Pomerania and that cooperation with Sweden would protect the duchy's constitutional and religious arrangements. Ferdinand II rejected this justification, and Imperial reprisals worsened the region's suffering.

Bogislaw died without issue in 1637, triggering a succession dispute between Sweden and Brandenburg. The eventual settlement at the Peace of Westphalia left western Pomerania with Sweden and eastern Pomerania with Brandenburg. The treaty is therefore an important step in the creation of Swedish Pomerania.