Some have argued that in A Tale of Two Cities Dickens reflects on his recently begun affair with eighteen-year-old actress Ellen Ternan, which was possibly platonic but certainly romantic. Lucie Manette has been noted as resembling Ternan physically.
After starring in a play by Wilkie Collins titled The Frozen Deep, Dickens was first inspired to write Tale. In the play, Dickens played the part of a man who sacrifices his own life so that his rival may have the woman they both love; the love triangle in the play became the basis for the relationships between Charles Darnay, Lucie Manette, and Sydney Carton in Tale.
Sydney Carton and Charles Darnay may also bear importantly on Dickens's personal life. The plot hinges on the near-perfect resemblance between Sydney Carton and Charles Darnay; the two look so alike that Carton twice saves Darnay through the inability of others to tell them apart. Carton is Darnay made bad. Carton suggests as much:
'Do you particularly like the man [Darnay]?' he muttered, at his own image [which he is regarding in a mirror]; 'why should you particularly like a man who resembles you? There is nothing in you to like; you know that. Ah, confound you! What a change you have made in yourself! A good reason for talking to a man, that he shows you what you have fallen away from and what you might have been! Change places with him, and would you have been looked at by those blue eyes [belonging to Lucie Manette] as he was, and commiserated by that agitated face as he was? Come on, and have it out in plain words! You hate the fellow.'
Many have felt that Carton and Darnay are doppelgängers, which Eric Rabkin defines as a pair "of characters that together, represent one psychological persona in the narrative". If so, they would prefigure such works as Robert Louis Stevenson's Dr. Jekyll and Mr. Hyde. Darnay is worthy and respectable but dull (at least to most modern readers), Carton disreputable but magnetic.
One can only suspect whose psychological persona it is that Carton and Darnay together embody (if they do), but it is often thought to be the psyche of Dickens himself. Dickens might have been quite aware that between them, Carton and Darnay shared his own initials. However, he denied it when asked.