Act I. A public place in Ferrara. On one side a palace. _Alfonso_,

who, incidentally, is _Lucrezia's_ fourth husband, she having done away with his predecessors by poison, or other murderous means, is jealous of _Gennaro_. Like the youth himself, he is ignorant that _Lucrezia_ is his mother, and is persuaded that he is her paramour. He has two solos. The first is "Vieni, la mia vendetta" (Haste then to glut a vengeance); the second, "Qualunque sia l'evento" (On this I stake my fortune).

[Music: Qualunque sia l'evento che può recar fortuna,]

_Gennaro_ and his friends come into the Plaza. They see the letters BORGIA under the escutcheon of the palace. _Gennaro_, to show his detestation of _Lucrezia's_ crimes, rushes up the steps and with his sword hacks away the first letter of the name, leaving only ORGIA. At the command of the _Duke_, he is arrested.

_Lucrezia_, not knowing who has committed the outrage, demands of her husband that its perpetrator be put to death. _Alfonso_, with cynical readiness, consents. _Gennaro_ is led in. _Lucrezia_ now pleads for his life. The _Duke_ is firm, even though _Lucrezia_ quite casually reminds him that he is her fourth husband and may share the fate of the other three. ("Aye, though the fourth of my husbands, you lord it.") His comment is the command that _Gennaro_ shall meet death by quaffing a goblet of poisoned wine handed to him by _Lucrezia_ herself. There is here a strong trio for _Lucrezia_, _Gennaro_, and _Alfonso_, as _Alfonso_ pours wine for himself and _Lucrezia_ from a silver flagon, while he empties the poisoned contents of a gold vessel, "the Borgia wine," into _Gennaro's_ cup. But _Lucrezia_ has the antidote; and, the _Duke_ having left her with _Gennaro_, in order that she shall have the pleasure of watching the death of the man of whom he suspects her to be enamored, she gives it to _Gennaro_, and bids him flee from _Ferrara_.