Editing Sigismund II Augustus (section)

==Third marriage==
[[File:Cranach the Younger Catherine of Austria.jpg|thumb|upright|Portrait of Catherine of Austria by [[Lucas Cranach the Younger]].]]

The death of Queen Barbara Radziwiłł, five months after her coronation and under distressing circumstances, compelled Sigismund to contract a third, purely political union with his first cousin, the [[Habsburg monarchy|Austrian]] archduchess [[Catherine of Austria, Queen of Poland|Catherine]], to avoid an Austro-Russian alliance. She was also the sister of his first wife, Elizabeth, who had died within a year of her marriage to him, before his accession. Catherine, unlike previous queens, was considered dull and obese. Sigismund Augustus found her immensely unattractive despite accepting the marriage and organizing a pompous wedding ceremony on 30 July 1553. On the other hand, Catherine showed resentment towards Sigismund because of how he treated her sister, Queen Elizabeth. She accused him of negligence and indifference during her sudden illness, which caused premature death. The correspondence between the two remained purely formal and political for the remainder of their lives.

Since her coronation, Catherine acted as Austria's puppet at the Polish court; she was tasked with [[espionage]] and obtaining important information for the benefit of the Habsburgs. Sigismund Augustus was aware of the scheme, but, by marrying Catherine, he obtained a promise from Austria to stay neutral and abandon plans with [[Tsardom of Russia|Russia]]. This neutrality was undermined by Catherine's actions, who followed her father's policy and objected the return of [[John Sigismund Zápolya]] and [[Isabella Jagiellon]] (Sigismund's sister) to Hungary. She would conspire with the Habsburg envoys prior to an audience with the king. She would also dictate what and how the envoys should express their views. When Sigismund Augustus found out of Catherine's intrigues, he sent her to [[Radom]] and excluded from political life.<ref>{{Cite web |url=http://www.marryingcultures.eu/research/elizabeth-catherine-austria |title=Elizabeth & Catherine of Austria |website=marryingcultures.eu |access-date=20 January 2024}}</ref>

As Sigismund lost all hope of children by his third bride, he was the last male Jagiellon in the direct line so the dynasty was threatened with extinction. He sought to remedy this by adultery with two of the most beautiful of his countrywomen, [[Barbara Giza]] (said to physically resemble late queen Barbara Radziwiłł) and [[Anna Zajączkowska]]. Barbara ultimately gave birth to a daughter, also named Barbara, whom Sigismund acknowledged as his child.<ref>{{Cite book |last=Borkowska |first=Urszula |title=Dynastia Jagiellonów w Polsce |publisher=PWN |year=2012 |isbn=978-83-01-16692-2 |page=565 |language=Polish}}</ref>

The King's marriage was a matter of great political import to [[Protestants]] and Catholics alike. The Polish Protestants hoped that he would divorce and remarry and thus bring about a breach with Rome at the very crisis of the religious struggle in Poland. He was not free to remarry until Catherine's death on 28 February 1572, but he followed her to the grave less than six months later.

His illegitimate daughter by Giza was adopted by her mother's new husband (Michał Woroniecki) and given stepfather's surname.<ref>Borkowska, Urszula (2012). ''Dynastia Jagiellonów w Polsce'' (in Polish). PWN. p.&nbsp;565. {{ISBN|978-83-01-16692-2}}.</ref>