Viola is the heroine of Twelfth Night, and along with Olivia, the play’s centre. However, whereas Olivia is more of a passive character (characters fall in love with her, and pursue her), Viola is active throughout: the catalyst who drives the plot on. This is even true in the one instance where Olivia is truly the active one: namely, when she falls in love with Viola (who is dressed as a boy, Cesario) and makes an effort to pursue ‘him’. As Viola is pursuing Olivia on behalf of her master, Duke Orsino, the two characters come to mirror each other more perfectly, with both of them ‘wooing’ the other, albeit for very different reasons.

Viola also shows considerable pluck and enterprise, making the most of her situation. She starts on the back-foot, unlike Olivia, who is rich (a countess), eligible (she’s unmarried), and did we mention rich? (since her father and brother have both died, the implication lurking behind the play, and behind both Sir Andrew’s and Malvolio’s interest in her, is that she possesses a vast fortune inherited from her male relatives).

Viola, by contrast, has been washed up on the shores of Illyria, with nothing to her name, and fearing her own twin brother, Sebastian, drowned. She immediately hatches the plan involving ‘Cesario’, her male alter ego, a eunuch who will enable her to enter the service of Orsino as a boy and thus get close to him.

Why does Viola want to serve Orsino? Her motive is difficult to analyse, although – like Malvolio, a character utterly unlike her in other ways – we cannot rule out ‘social advancement’. In I.2, when she has the conversation with the sea captain, she casually drops into conversation that Duke Orsino, who rules Illyria, was a ‘bachelor’ the last time she heard his name mentioned. Has she got designs on the Duke’s fortune, and spies an opportunity to make her way in this new land? However, she then learns that Orsino is trying to woo Olivia, so she may have identified a role for herself: to play matchmaker for Orsino, by acting as the go-between and to try to win Olivia for him.

Viola’s adoption of a male disguise – the character of ‘Cesario’ – is liberating but also, ultimately, restrictive. It allows her to enter the service of the Duke Orsino and eventually to marry him. But within the action of the play, she becomes trapped in a false world of pretence, where she can never tell Orsino how she really feels. She must always be playing a part, the part of somebody – Cesario – who doesn’t actually exist. Nevertheless, after Olivia and Malvolio, the character of Viola is the one that provides the most scope and potential for an actor: she is more than just the comic catalyst for the play’s action. After all, for much of the play she is unsure whether her twin brother is dead or alive. Notable actors who have played the role of Viola have included Anne Hathaway, Tallulah Bankhead, and Eddie Redmayne, who made his professional stage debut in the role for a Shakespeare’s Globe in 2002.