Joanna of Austria (1535-1573) was a Spanish princess and the daughter of Holy Roman Emperor Ferdinand I and Anna of Bohemia and Hungary. She was born in Vienna and became known for her marriage to Prince John of Portugal, which was part of a political alliance between the Habsburgs and the Portuguese crown. Joanna's life was marked by her role as a mother to several children, including Catherine of Portugal, who later became Queen of England. Despite her noble lineage, Joanna faced challenges, including the early death of her husband and the political turmoil of her time, which shaped her legacy in European history.