Legal debates on the deposed sovereigns’ rights have emerged since 20th century. Among them, the right to appoint knights by heads of deposed royal families is one of the focal points. The author begins with a comprehensive review of legal debates on the subject. Six principles on the appointment are extracted from the review. Then, a new interpretation is proposed, wherein the legitimacy to confer honours and the legitimacy of the orders of knighthood themselves have to be considered separately. Under this method of interpretation, the criterion to judge the legitimacy of an appointment of knight is both the jus honorum of the head of the family and the order of knighthood itself being legitimate.