In March 1552, he called her mother, her aunt Martha and her spouse, and the King's nephew Per Brahe the Elder who was married to Catherine's sister Beata, and it thought that her proposed the marriage to her family at this meeting.

[1] The reason the King stated to marry Catherine was the great costs and the time-consuming negotiations necessary secure a marriage with a foreign princess in the complicated political climate in Europe during the ongoing religious conflicts.

Her private relationship to the King is not much mentioned, and it has been said that she: "Accepted her part as Queen of Sweden with silent dignity" and without attracting too much personal attention.

It is said, however, that the King did find their age difference too great and contemplated writing a law which would prevent any future marriage between: "Two people, of which one was young and one was old".

She accompanied Cecilia to her confrontation with her father after her return to the capital, and she acted as channel through the King for Princess Catherine, who tried to negotiate Johan's release and permission for her and her spouse to leave for East Frisia.

In his will, Catherine was promised custody of the Princesses, who were to live at the court of Eric or her until they married, an allowance suitable for her position, and that his sons should always see to it that she had her needs taken care of.

[1] In March, Catherine had Eric XIV issue a written statement of her right to Strömsholm, which remained her seat for the rest of her life, as well as several other lands and parishes in Sudermannia, as well as her own residence in the capital.

[1] The mother of the new King's infamous adviser Jöran Persson, Anna, was the house keeper of the Queen Dowager's court at Strömsholm.

During most of the reign of Eric XIV, the King was unmarried, and Queen Dowager Catherine ceremoniously functioned as the first lady of the royal court.

[1] Queen Dowager Catherine seems to have had a good relationship to Eric XIV, who normally treated her with respect, referred to her as "My Dear Stepmother" and trusted her on certain critical occasions.

[1] He gave her a written document giving her the authority to negotiate the settlement with the relatives of the murder victims, among them her aunt Martha Leijonhufvud.

[1] Through Catherine, Martha Leijonhufvud put forward her demands of a letter of protection against further persecution of the King; an official statement of the innocence of the murder victims; economic compensation and the arrest of the people truly responsible for the behavior of the monarch, which was regarded to be his adviser Jöran Persson.

During the illness and convalescence of the King, the Kingdom was ruled by a regency council including the uncles of Catherine, Per Brahe the Elder and Sten Leijonhufvud.

[1] Eric XIV had made an alliance with Russia against Poland, and the Tsar had presented the demand that he should give him his Polish sister-in-law, the spouse of Prince John, Princess Catherine Jagellon, as hostage to use against Poland, and a Russian embassy was at the time waiting in Stockholm to bring Catherine Jagellon to Russia.

[1] Eric XIV felt forced to decline this demand because of international pressure, but had offered to replace his Polish sister-in-law with his stepmother and his two sisters.

[1] According to John, the relationship between the King and the Queen Dowager was bad at this point, as he had accused her of having financed the Danes during the ongoing Northern Seven Years' War and threatened not only to give her, his sisters and their ladies-in-waiting over to the Russians but also to burn them alive.

[1] It is unclear how much of this is true and what is propaganda from the later John III to excuse the deposition of his brother, but what ever the case, Queen Dowager Catherine and Princesses Sophia and Elizabeth left the court and escaped to join the rebellious Dukes after having been given a threat of some kind by the King, likely when they were told of their planned Russian captivity.

[1] One version said that they were permitted to take a boat trip and continued until the other shore, and another one that they took a walk in the town and continued to the city gate: in any case, when they had left town, they were joined by the spouse of Princess Sophia, Magnus II of Saxe-Lauenburg, who had been sent by the King to pursue his brothers, but who instead took the Queen Dowager and the Princesses to join the rebels.

[1] During the following imprisonment of Eric XIV and Karin, their children were placed in the custody of Catherine Stenbock and their French governess Johanna (Jeanne) de Herboville from 1568 until 1570.

[3] Eric XIV had a good relation to Catherine: even after having been attacked by her brother Olof in prison, he gave her the credit for not having been put to death after his dethronement.

Her estates made it possible for her to act as one of the foremost financiers of John III, particularly in his war with Russia, loans he was unable to pay her back.

The conflict, however, continued until 1582, when John III formally had the royal council declare a verdict in favor of Catherine in the matter and threaten Charles with the loss of his succession rights to the throne unless he respected the decision.

[1] During the time of conflict between her and Duke Charles of the rights to Strömsholm (circa 1580), she received a proposal from a German Count Palatine, but declined the offer.

[1] In 1574, a scandal took place when her brother Erik Stenbock made his legendary elopement with their cousin, Malin Sture, daughter of her famous aunt Martha Leijonhufvud.

Her brothers refused to join Duke Charles, who declared them, her brother-in-law Klaus Fleming, Governor of Finland, and her nephew as his enemies.

Among the female relations she received as maid of honor were Ebba Brahe in 1614, who was the removed from the employ of the mother of Gustavus Adolphus of Sweden to prevent a love match with the King, and whose wedding she hosted in 1618.

Queen Dowager Catherine Stenbock spent her last years tending to her estates, engaging in iron works and other enterprises, and spending time with her relatives, especially her sisters.

She has been given a charitable reputation because she gave a safe haven to many female relations to the exiled loyalists of Sigismund, and because she often acted as a channel of the local peasantry and the royal house.