Sydney Carton of A Tale of Two Cities figures well as the archetype of the martyr. Certainly, he is somewhat tortured by his legal partner, C. J. Stryver who keeps the passive Carton awake half the night preparing for him a defense of Charles Darnay against the charges of treason. Chapter V of Book the First presages Carton's role as martyr as he leaves Stryver's office:
Waste forces within him, and a desert all around, this man stood still on his way across a silent terrace, and saw for a moment, lying in the wilderness before him, a mirage of honourable ambition, self-denial, and perseverance.
Further, in Chapter XIII of Book the Second, the reader perceives Carton taking on an almost mythical aspect of the martyr as he professes his willingness to sacrifice himself to save his friends. He tells Lucie,
For you, and for any dear to you, I would do anything. If my career were of that better kind that there was any opportunity or capacity of sacrifice in it, I would embrace any sacrifice for you and for those dear to you.
Finally, in Book the Third, Sydney Carton truly becomes the martyr, an almost Christ-like figure, who lays down his life for the salvation of Charles Darnay, whom Lucie loves dearly. Fulfilling his pledge of devotion to Lucie, Carton recalls the words of Christ as he mounts the steps to the guillotine:
"I am the Resurrection and the life, saith the Lord: he that believeth in me, though he were dead, yet shall he live: and whosoever liveth and believeth in me, shall never die."
With his death, Carton achieves a certain immortality and sainthood as Lucie and Charles Darnay "hold a sanctuary" in their hearts for him and name their son after him.
Charles Darnay fits "the Hero" archetype. The "hero" traditionally goes on some sort of quest and uses qualities, traits, or characteristics that make him admirable. He separates himself from the Marquis and his family legacy, claiming:
"This property and France are lost to me. I renounce them." (Book 2, chapter 9)
Fitting the archetype mold, Darnay has these noble characteristics of honor, respect, and courage. Darnay may be more of a flat character than Carton, but he still exhibits courage when facing difficulty, for example when he makes the decision to return to France.
"[B]ad aims were being worked out in his own unhappy land by bad instruments, and that he who could not fail to know that he was better than they, was not there, trying to do something to stay bloodshed, and assert the claims of mercy and humanity." (Book 2, Chapter 24)
mwestwood, could you please cite the quotes? would be a big help