Who is The Lady Edith from The Prince and the Pauper and what is their importance?

Lady Edith is Hugh and Miles Hendon's cousin. She is the love of Miles' life, but she is forced to marry Hugh it is believed that Miles is dead. When Miles miraculously returns, Hugh forced Edith to deny that she recognizes him..... if she does, Hugh promises his brother will die. Over the course of the novel, Edith and Miles and reunited after Hugh's death.