Catherine of Austria (; 14 January 1507 – 12 February 1578) was Queen of Portugal as wife of King John III, and regent during the minority of her grandson, King Sebastian, from 1557 until 1562. Early life An Infanta of Castile and Archduchess of Austria, Catherine was the posthumous daughter of King Philip I by Queen Joanna of Castile. Catherine was born in Torquemada and named in honor of her maternal aunt, Catherine of Aragon. She remained with her mentally unstable mother. All of her five older siblings, except Ferdinand, were born in the Low Countries and had been put into the care of their aunt Margaret of Austria, but Joanna kept hold of young Catherine. Catherine actually stayed with her mother during imprisonment at Tordesillas during her grandfather Ferdinand of Aragon's time as regent and her elder brother Carlos as co-king. When the time came for her to marry, Catherine was released from the custody that her mother was to endure until her death. Queen On 10 February 1525, at the age of 18, Catherine married her first cousin, King John III of Portugal, she was married off to him by her mother Joanna I of Castile. They had nine children, but only two survived early childhood. Catherine was very concerned about the education of her family, accumulating a substantial library and establishing a kind of salon in the court. She brought a number of women scholars into her household, including the humanists Joana Vaz and Públia Hortênsia de Castro, and the poet Luisa Sigea de Velasco. Vaz was responsible for tutoring Catherine's daughter, Princess Maria, as well as Catherine's niece, also called Maria, and a scholar in her own right. After the death of her husband in 1557, she was challenged by her daughter-in-law and niece, Joan of Austria, over the role of regent for her grandchild, the infant King Sebastian. Mediation by Charles V resolved the issue in favour of his sister Catherine over his daughter Joan, who was needed in Spain in the absence of Philip II. She then served as the regent of Portugal from 1557 until 1562. In 1562, she turned over the regency to Henry of Portugal. Collector Catherine had one of the earliest and finest Chinese porcelain collections in Europe due to her position as both the youngest sister of Emperor Charles V and the Queen of Portugal. "She acquired quantities of