Eric IV, also known as Eric Ploughpenny or Eric Plowpenny (Danish: "Erik Plovpenning" ), (  1216 – 10 August 1250) was king of Denmark from 1241 until his death in 1250.
 He was the son of King Valdemar II by his wife, Berengaria of Portugal, and brother of King Abel and King Christopher I.
Jutta of Saxony (c. 1223 – before 2 February 1267) was a Danish Queen consort, spouse of King Eric IV of Denmark.
 Jutta was the daughter of Albert I, Duke of Saxony.
 She married king Erik in 1239, and became junior queen consort, since her husband was junior king, even though there were no senior queen at the time.
 She would become senior queen in 1242.
Jutta Ditfurth (born "Jutta Gerta Armgard von Ditfurth", September 29, 1951 in Würzburg) is a German sociologist, writer, and radical ecologist politician.
 Being born into the noble house of Ditfurth, members of which had been noble ministeriales invested with hereditary administrative titles and offices in various regions of today's Saxony-Anhalt and Lower Saxony and elsewhere in the Holy Roman Empire, a daughter of the German physician and science journalist Hoimar von Ditfurth and a sister of the historian Christian von Ditfurth, in 1978 she attempted to have her name legally changed to remove the nobiliary particle "von" and to become the plainer "Jutta Ditfurth", but was refused the change by the authorities.
 She is nonetheless known throughout Germany by her adopted non-noble name, which she prefers.
Jutta of Denmark also known as "Judith" (1246-1286/95) was a daughter of Eric IV of Denmark and his wife Jutta of Saxony.
 She was a younger sister of Queen Sophia of Sweden, and Queen Ingeborg of Norway, as well as an older sister of Agnes.
 Jutta was also mistress for a brief period of time to her brother-in-law Valdemar, King of Sweden.
 Jutta was a member of the House of Estridsen.
Agnes of Denmark (1249-after 1290) was the youngest daughter of Eric IV of Denmark and his wife Jutta of Saxony.
 She founded the Convent of St. Agneta in Roskilde, becoming Abbess there.
Kunststätte Bossard is an expressionist "Gesamtkunstwerk", sometimes also referred to as a visionary environment, located in the town of Jesteburg in Lower Saxony, Germany.
 It was created by Swiss artist (1874-1950) and his wife, Jutta Kroll-Bossard (1903-1996).
 It combines architecture, sculpture, painting and garden design.

Question: Who was Jutta of Saxony's father-in-law?
Answer: King Valdemar II