|Date of birth|
|Date of death||1371 Hesse|
Adelaide of Hesse (Polish: Adelajda heska) (b. after 1323, d. after May 26, 1371) was a daughter of Henry II, Landgrave of Hesse, and his wife Elisabeth of Thuringia, daughter of Frederick I, margrave of Meissen. Adelaide was a member of the House of Hesse.
She was named after her paternal grandmother.
On September 29, 1341 in Poznań, Adelaide married Casimir III the Great, King of Poland. The marriage was result of agreement between Casimir III and Luxemburgs.
This was Casimir's second marriage, after the death of his first wife, Aldona of Lithuania. Casimir had no male heir, though he had two daughters, Elizabeth and Kunigunde. On September 29, 1341, Adelaide was crowned in Poznań Cathedral. The marriage was very unhappy, Casimir started living separately from Adelaide soon after their marriage.
Their loveless marriage lasted until 1356. Casimir separated from Adelaide and married his mistress Christina. Christina was the widow of Miklusz Rokiczani, a wealthy merchant. The bigamy and his womanizing Casimir got into severe trouble with the clergy.
Casimir continued living with Christina despite complaints by Pope Innocent VI on behalf of Adelaide. The marriage lasted until 1363/1364 when Casimir again declared himself divorced. They had no children. The marriage to Adelaide was annulled in 1368. Then Casimir married his fourth wife Jadwiga (Hedwig) of Żagań. This marriage produced another three daughters.
With Adelaide still alive and Christina possibly as well, the marriage to Jadwiga was also considered bigamous. The legitimacy of the three last daughters was disputed. Casimir managed to have two of his daughters, Anna and Kunigunde legitimatized by Pope Urban V on December 5, 1369. Jadwiga the younger was legitimatized by Pope Gregory XI on October 1, 1371.
After the annulment of her marriage, Adelaide went back home to Hesse. She spent the rest of her life in Hesse.
After her ex-husband's death, she fought for her property rights. She intervened in this case to the pope Greogry XI. On May 26, 1371 pope urged king Louis to give back her property.