 Born in Nomeny in the Duchy of Bar, Louise was the third daughter and youngest child of Nicholas of Lorraine, Duke of Mercœur, and Countess Marguerite d'Egmont.She was the only surviving child of her parents; her older siblings, two sisters and one brother, died in infancy.Louise's mother died shortly before her first birthday in 1554, and her father quickly remarried in 1555 Princess Joanna of Savoy-Nemours, and gave Louise a solid classical education and introduced her to Nancy's court at the age of ten.