The Duke of York became a Roman Catholic in 1668 or 1669, but Mary and Anne had a Protestant education, as Charles II had commanded. Mary's mother died in 1671, and her father married again in 1673. He took Mary of Modena, a Catholic, as his second wife. She was also known as Mary Beatrice d'Este. Before her marriage, Mary wrote many letters to Frances Apsley, the daughter of James II's hawks keeper. However, she did not return Mary's interest.