 The sailors are persuaded by her discourses during the voyage to take a part in the insurrection, which Cythna arrives in time to lead.The merciless slaughter which followed the suppression of the revolt by the mercenary troops of the Tyrant's allies has led to a devastating plague accompanied by famine.The allies each invoke their separate Gods to relieve them of the pestilence, and resolve (at the suggestion of one "Iberian priest") to offer Cythna and Laon as a sacrifice to the deity; whoever locates them will receive the tyrant's daughter in marriage.