Madeleine Allsopp is the daughter of Lord Aysgarth and a friend of Rose MacClare.
Background
Madeleine's father holds a low barony title in English peerage, so she is known as an "Honorable" rather than a "Lady".
2013 Christmas Special
Both Rose and Madeleine are presented before King George V, Queen Mary, and his eldest son, the Prince of Wales at Buckingham Palace in 1923.
She is encouraged by her father, who has little money, to have an interest in rich men Harold Levinson. She ends up liking Harold from the heart and was upset that he had to go back to America. She also decides not to be a part of her father's schemes anymore. Harold in turn begins to like her more.