Who is Lady Markby from the play, An Ideal Husband?

Lady Markby is Mrs. Cheveley's immediate connection to London society, as Mrs. Cheveley is younger and has traveled to London from Vienna alone. Lady Markby introduces Mrs. Cheveley to persons whom she does not yet know and chaperones the younger woman around town. She is an established, well-liked, older member of the moneyed, aristocratic society depicted in Wilde's play.