Towards the end of The Changeling (1653), after De Flores stabs Beatrice-Joanna and then reveals that the two of them have been murderers and lovers, the dying Beatrice-Joanna says to her shocked father:
O come not near me, sir, I shall defile you:
I am that of your blood was taken from you
For your better health.Middleton, Thomas, and William Rowley. The Changeling. 1653. Thomas Middleton: Five Plays. Eds. Bryan Loughrey and Neil Taylor. London: Penguin Classics, 1988: 345–421. V.3.149–151, p. 419.
Isolated from the metaphor of bloodletting, the line I am that of your blood was taken from you suggests that the original Beatrice-Joanna was kidnapped by magic, and an evil substitute (a changeling) left in her place. One can see either Beatrice-Joanna's falling in love with Alsemero despite her engagement to Alonzo, or her thralldom to De Flores after he kills Alonzo at her behest, as the moment of evil enchantment when a corrupt Beatrice-Joanna replaces the hitherto virtuous one.
Yet the cast of characters (p. 346) lists an entirely different character as "the changeling": Antonio, a courtier who pretends to be mentally deficient so as to woo Isabella, the wife of the jealous keeper of the lunatic asylum. The parallels between the Isabella sub-plot and the main narrative of Beatrice-Joanna are readily discernable. But I do not understand what makes Antonio the changeling. Why is this relatively minor character supposedly the titular changeling? It cannot be simply that he pretends to be someone else, because that applies equally to Franciscus, who is described in the cast of characters as "the counterfeit madman." So what about Antonio's role is important enough to name the play after him or vice-versa?
