Bogislaw IV, Duke of Pomerania

Bogislaw IV (Polish: Bogusław IV; died 19 February 1309 or 24 February 1309), of the Griffins dynasty, was Duke of Pomerania for thirty years.

Bogislaw was the eldest son of Duke Barnim I by his first wife, sometimes said to be a daughter of King Eric X of Sweden. He was an adult at his father's death in 1278, having been co-ruler since 1276. His half-brothers Barnim II and Otto I were still very young and so he was sole ruler in Pomerania during their minority.

In the early 1280s Bogislaw was involved in the war in the neighbouring margraviate of Brandenburg. At this time he married Matilda, daughter of John I and a sister of reigning Margrave Otto IV, but all of his known children were by a second marriage to Margarete, daughter of Wizlaw II, Prince of Rügen.

In the 1290s with his brothers now adults, Pomerania was divided between them with Bogislaw receiving Wolgast as his share. Barnim II died soon afterwards and Otto ruled Szczecin.

In the 14th century, he was allied with would-be King of Poland Władysław the Short. He was unsuccessfully involved in the opening stages of the decade-long Brandenburg War. He died in 1309 leaving his share of Pomerania to his son Wartislaw.

He firstly married Matilda of Brandenburg-Stendal, daughter of John I, Margrave of Brandenburg. He married secondly Margarete of Rügen, daughter of Wizlaw II, Prince of Rügen. His children from his second marriage were:

• Euphemia of Pomerania married Christopher II of Denmark
• Wartislaw IV, Duke of Pomerania, would later rule in Western Pomerania and inherit Rügen
• Elisabeth of Pomerania (1291–1349) married Duke Eric I of Saxe-Lauenburg ca. 1318
• Jutta
• Margareta, wife of Nicholas I, Lord of Rostock
• possibly another daughter, Euphemia, wife of Adolph V, Count of Holstein-Segeberg