Countess Consort. Princess of Sweden, Vasa Dynasty, daughter of King Carl IX and Duchess Maria. Mother of King Carl X Gustav. Her mother died in 1589. In 1592, her father was remarried to Princess Christina of Holstein-Gottorp. She reportedly got along well with her stepmother and was close to her half siblings, especially her eldest brother, the future King Gustav II Adolph, who is noted to have been very fond of her. In later letters to her consort, however, she was not always as much in agreement with her stepmother as she gave the impression of. Her father was crowned King in 1607. In 1611 he died, and her brother succeeded her father as King. She acted as his confidante and adviser on several occasions. Catherine married late for a princess of her period. Although she was a great heiress, her status on the international royal marriage market was uncertain because of the political situation in Sweden after her father had conquered the throne from his nephew King Sigmund. After the Treaty of Knäred in 1613, her status became more secure. With the support of her stepmother Queen Dowager Christina, the queen dowager's brother Archbishop John Frederik of Bremen arranged the marriage between Catherine and her relative Count Palatine John Casimir of the Palatinate-Zweibrücken. Though relatively poor, he had contacts which were deemed valuable to Sweden. The marriage took place on 11 June 1615 in Stockholm. Catherine was, by the will of both her parents as well as by the law regarding the dowry of Swedish Princesses, one of the wealthiest heiresses in Sweden. She remained in Sweden the first years after her marriage to guard her interests. but 1618 left for Germany where the couple was given Kleeburg Castle in Northern Alsace as their residence. The year after, John Casimir started to build a new residence, Katharinenburg Palace near Kleeburg. In 1620, the Thirty Years' War forced them to flee to Strassburg and return to Sweden. The death of her younger brother in Sweden, as well as the lack of heirs to the Swedish throne was evidently the reason why the monarch wished to move her to safety away from the war. Catherine arrived in Sweden with her family in 1622. After that, the birth of her son Carl Gustav immediately strengthened her position. She and her husband were granted Stegeborg Castle and a county in East Gothland as their fief and residence and as payment of her dowry: Catherine was styled Countess of Stegeborg. She maintained a royal standard of living: they kept a court with sixty formal ladies-in-waiting and courtiers and an official table, and Catherine was actively involved in the management of the estates, in 1626 also being given Skenäs royal estate as her personal fief. During the King's trips, he often asked Catherine to try to console and control his consort Queen Mary Eleanor. Though the object to a few intrigues at court to blacken her name with the royal couple, Catherine managed to avoid these plots. In 1631, Princess Catherine was given the custody of her niece Princess Christina, the heir to the throne when the Queen was allowed to join the king in Germany where he was at war. Christina remained in her care until Mary Eleanor returned to Sweden at the death of Gustav II Adolph the next year. Catherine and her husband came in conflict with the Regency of Queen Christina over their position and rights to Stegeborg. John Casimir broke with the Royal Council in 1633 amd the couple retired to Stegeborg. Catherine did not show any interest in government affairs. In 1636, however, Queen Dowager Mary Eleanor was deemed unfit to have custody of the young monarch Christina, and Catherine was appointed official guardian and foster mother, responsible for the girl's upbringing. This appointment destroyed her relationship with Mary Eleanor. The years in Catherine's care are described by Christina as happy ones. Princess Catherine personally enjoyed respect and popularity in Sweden. John Casimir was careful to point out her status as a Royal Princess, but was himself exposed to some humiliation because of their difference in rank. Catherine died in West Aros, where the royal court had fled from an outbreak of the plague in Stockholm. At her death, powerful Count Axel Oxenstierna said that he would rather have buried his own mother twice, than have seen "the premature death of this noble Princess". She had born John Casimir 8 children, of which 2 sons and 3 daughters survived childhood.