Shakespeare drew on Plutarch’s ‘Life of Marcus Antonius’ for Julius Caesar (1599) and again for Antony and Cleopatra (1606?). When writing Coriolanus, he would have found the ‘Life of Alcibiades’ paired with that of Coriolanus. Both of these ‘Lives’ mention Timon, and so it is possible to imagine Shakespeare encountering the figure as he revisited Plutarch when working on the late Roman plays.
