"Joanna of Austria (in Castilian, doña Juana de Austria; in Portuguese, Dona Joana de Áustria, 24 June 1535 – 7 September 1573) was Princess of Portugal by marriage to John Manuel, Prince of Portugal. She served as regent of Spain to her brother Philip II of Spain during his trip to England to marry Mary I in 1554-1556, and from 1556 to 1559. She was the mother of King Sebastian of Portugal." - (en.wikipedia.org 03.10.2020)