Question: is it illegal to use a different name

title: Name change
text: From the mediaeval age to the 19th century , the era of family dynasties , name changes were frequently demanded of heirs in the last wills and testaments , legacies and bequests , of members of the gentry and nobility who were the last males of their bloodline . Such persons frequently selected a younger nephew or cousin as the heir to their estates on condition that he should adopt the surname and armorials of the legator in lieu of his patronymic . Thus the ancient family otherwise destined to extinction would appear to continue as a great dynasty in the making . Such changes were also more rarely demanded by marriage settlements , for example where the father of a sole daughter and heiress demanded that as a condition of his daughter 's dowry her husband should adopt his father - in - law 's surname and arms . Thus the progeny of the marriage would continue the otherwise extinct family 's name . Such name changes were generally only demanded of younger sons , where an elder brother was available to inherit the paternal estates under primogeniture and carry on the name and arms abandoned by the younger brother . Such name changes were effected by obtaining a private Act of Parliament or by obtaining a Royal Licence . A less radical procedure adopted from the 18th century onwards was for the legator or settlor to demand only that the legatee or beneficiary should adopt his surname in addition to his patronymic , not in place of it , which gave rise to the `` double - barrelled '' , even the `` triple - barrelled '' name , frequently parodied in literature as epitomising the wealthy `` squirearchy '' with an embarrassment of inherited estates .