instead of keeping his vow, he ordered the jailer to present Cassandra with her brother’s head.  As the jailer knew what the governor had done, he took the head of a felon just executed, and set Andrugio at liberty.  Cassandra, supposing the head to be her brother’s, was at the point to kill herself for grief, but spared that stroke, to be avenged on the traitor.  She devised to make her case known to the King; who forthwith hastened to do justice on Promos, ordering that, to repair the lady’s honour, he should marry her, and then, for his crime against the State, lose his head.  No sooner was Cassandra a wife than all her rhetoric of eye, tongue, and action was tasked to procure the pardon of her husband; but the King, tendering the public good more than hers, denied her suit.  At length, Andrugio, overcome by his sister’s grief, made himself known; for he had all the while been about the place in disguise; whereupon the King, to honour the virtues of Cassandra, pardoned both him and Promos.

In 1592, Whetstone published his Heptameron of Civil Discourses, containing a prose version of the same tale.  It is observable that he deviates from Cinthio in bringing Andrugio off alive; and as Shakespeare does the same with Claudio, we may well conclude that he drew directly from Whetstone, not from the original author.  Beyond the mere outline of the story, it does not appear that the Poet borrowed any thing more than a few slight hints and casual expressions.  And a comparison of the two pieces would nowise reduce his claims; it being not less creditable to have lifted the story out of the mire into such a region of art and poetry than to have invented it.  Then too, even as regards the story, Shakespeare varies from Whetstone much more materially than the latter does from Cinthio:  representing the illicit meeting of Claudio and Juliet as taking place under the shield of a solemn betrothment; which very much lessens their fault, as marriage bonds were already upon them; and proportionably heightens Angelo’s wickedness, as it brings on him the guilt of making the law responsible for his own arbitrary rigour.  But the main original feature in the plot of Measure for Measure is the part of Mariana, which puts a new life into the whole, and purifies it almost into another nature; as it prevents the soiling of Isabella’s womanhood, supplies an apt reason for the Duke’s mysterious conduct, and yields a pregnant motive for Angelo’s pardon, in that his life is thereby bound up with that of a wronged and innocent woman, whom his crimes are made the occasion of restoring to her rights and happiness; so that her virtue may be justly allowed to reprieve him from death.