Christina of Denmark was a Danish princess, the younger surviving daughter of King Christian II of Denmark and Norway and Isabella of Austria. By her two marriages, she became Duchess of Milan, then Duchess of Lorraine. She served as the regent of Lorraine from 1545 to 1552 during the minority of her son. She was also a claimant to the thrones of Denmark, Norway and Sweden in 1561–1590 and was sovereign Lady of Tortona in 1578–1584.

Isabella of Austria, also known as Elizabeth, was born an Archduchess of Austria and Infanta of Castile from the House of Habsburg, and subsequently became Queen of Denmark, Norway and Sweden, under the Kalmar Union, as the wife of King Christian II. She was the daughter of King Philip I and Queen Joanna of Castile and the sister of Charles V, Holy Roman Emperor. She ruled Denmark as regent in 1520.