Marie Casimire Louise de La Grange d'Arquien

Marie Casimire Louise de La Grange d'Arquien, known also by the diminutive form "Marysieńka", was a French noblewoman who became the queen consort of Poland and grand duchess consort of Lithuania from 1674 to 1696 by her marriage to King and Grand Duke John III Sobieski of the Polish–Lithuanian Commonwealth. She had great influence upon the affairs of state with the approval of her spouse, and acted in effect as regent during his absence.