"Maria Euphrosyne of Zweibrücken (14 February 1625, Stegeborg Castle, Östergötland – 24 October 1687, Höjentorp Castle, Västergötland), was a countess palatine, a cousin and foster-sibling of Queen Christina of Sweden, and a sister of King Charles X of Sweden. She was also, after the accession of her brother Charles X on the throne (1654), a titular Royal Princess of Sweden." - (en.wikipedia.org 31.10.2019)