Question: Bogusław I, of the House of Griffins was Duke of Pomerania-Stettin from 1156 to 1187, he was first married to Walburgis (d. 1177), daughter of which King of Denmark from 1146 until his death in 1182?
Context: Bogusław I (also Bogislaw and Boguslaus;  1130 – 18 March 1187 in Sosnitza near Altwarp) of the House of Griffins was Duke of Pomerania-Stettin from 1156 to 1187.  He ruled the Duchy of Pomerania jointly with his brother Casimir I of Pomerania-Demmin.  His father was Wartislaw I.  He was first married to Walburgis (d. 1177), daughter of Valdemar I of Denmark and later to Anastasia, daughter of Mieszko III of Poland and Eudoxia of Kiev.  With his second wife, he had 5 children. Valdemar I of Denmark (14 January 1131 – 12 May 1182), also known as Valdemar the Great (Danish: "Valdemar den Store" ), was King of Denmark from 1146 until his death in 1182. Henry II (German: "Heinrich" , 1112 – 13 January 1177), called Jasomirgott, was the Count Palatine of the Rhine from 1140 to 1141, the Margrave of Austria from 1141 to 1156, the Duke of Bavaria from 1141 to 1156 as Henry XI, and the Duke of Austria from 1156 to 1177.  He was a member of the House of Babenberg. Bogislaw II (  1177 – 23 January 1220) was Duke of Pomerania-Stettin from 1187 until his death. Eric III Lamb (Danish: "Erik III Lam" ) (  1120 – 27 August 1146) was the King of Denmark from 1137 until 1146.  He was the grandson of Eric I of Denmark and the nephew of Eric II of Denmark, whom he succeeded on the throne.  He abdicated in 1146, as the first and only Danish monarch to do so.  His succession led to a period of civil war between Sweyn III, Canute V, and Valdemar I. Duke Casimir V of Pomerania (or, counting differently, Casimir VI; before 1380 – 13 April 1435) was a member of the House of Griffins and a Duke of Pomerania.  He ruled in Pomerania-Stettin together with his brother Otto II from 1413 to 1428.  After 1428, he ruled Pomerania-Stettin alone. Swantibor III, Duke of Pomerania, or, according to a different way of counting, Swantibor I. (born:  1351 – died: 21 June 1413) was a member of the House of Griffins, a Duke of Pomerania-Stettin and for a while governor of the Mittelmark. Otto III, Duke of Pomerania (29 May 1444 – 7 September 1464) was a member of the House of Griffins and a Duke of Pomerania-Stettin. The House of Griffins or House of Pomerania (German: "Greifen" ; Polish: "Gryfici" ), also known as "House of Greifen", was a dynasty of dukes ruling the Duchy of Pomerania from the 12th century until 1637.  The name "Griffins" was used by the dynasty after the 15th century and had been taken from the ducal coat of arms.  Wartislaw I (around 1091 – died August 9, 1135) was the first historical ruler of the Duchy of Pomerania and the founder of the Griffin dynasty.  The most prominent Griffin was Eric of Pomerania, who became king of the Kalmar Union in 1397, thus ruling Denmark, Sweden and Norway.  The last Griffin duke of Pomerania was Bogislaw XIV, who died during the Thirty Years' War, which led to the division of Pomerania between Brandenburg-Prussia and Sweden.  Duchess Anna von Croy, daughter of Duke Bogislaw XIII and the last Griffin, died in 1660. Ratibor I ("Racibor") ( 1124 – 1156) of the House of Pomerania ("Griffins") was Duke of Pomerania.  He was married to Pribislawa, and was the ancestor of the "Ratiborides" sideline of the Griffins.
Answer: Valdemar I of Denmark