Posthumus Leonatus is a young man of good family whose father died before his birth.
Brought up by Cymbeline almost as a son, he is nevertheless too poor to be considered by him for a son-in-law, and is banished when he dares to marry his childhood companion, the Princess Imogen. He is renowned as being one of the best of men, courteous, well-trained, and educated, but also a man not afraid of a quarrel. He rests an infinite trust in Imogen’s faithfulness, to the extent of being willing to make a very stupid bet on it; he is in fact quite easily convinced that she is false, and his loathing of her becomes as great as was his love. His deception turns him into a rampant misogynist and a murderer-by-proxy. He repents when he is convinced that Imogen is dead, however, and turns suicidal. He is not a subtle man, nor one to do things by halves. He blames Italy for having changed him into a murderer, and takes on all the penance he can when he returns to Britain to atone for his deeds. Recovering Imogen, he is magnanimous, and pardons Jachimo, the chief cause of his unhappiness. Posthumus suffers from his lack of family. He is a well-shaped man, physically the same dimensions as Cloten.