Posthumus's only visible action is to agree to the wager with Iachimo that tests Imogen's chastity. It is a swaggering, boys-will-be-boys wager (based on a well-known episode in The Decameron of Boccaccio, and on a sixteenth-century pamphlet called “Fred-eryke of Jennen”) that leads to separation and loss, and almost to tragedy. From an actor's point of view, Posthumus is a fairly thankless role.
