Explain why the following quote is ironic from The Taming of the Shrew.
"Lucentio! O, he hath murdered his master!-Lay hold on him , I charge you, in the duke's name.-O, my son, my son!-tell me, thou villain, where is my son, Lucentio?" (Vincentio-V.i.85-90
You have identified an excellent piece of dramatic irony in the final act of this hilarious play. Let us remember the situation - Tranio is dressed up as Lucentio, with the Pedant playing the part of his "father," and then the real Vincentio arrives. Seeing Tranio dressed up as a noble, he assumes the worst and the Pedant's protestations that he is the real father of the Lucentio that Tranio is playing makes Vincentio come to the conclusion that Tranio has actually killed Lucentio and has impersonated him to gain his wealth. Thus Vincentio calls for Tranio to be arrested for the murder of his son.
This is an excellent example of dramatic irony because Vincentio doesn't know what we and other characters on stage know - that Tranio has not killed Lucentio and that Lucentio is alive and well, and in fact this is all part of an elaborate plot to ensure he marries the woman of his dreams.