Henry IV Part 1
How we cite our quotes:
Our house, my sovereign liege, little deserves
The scourge of greatness to be used on it;
And that same greatness too which our own hands
Have holp to make so portly. (1.3.1)
When King Henry threatens the Percys for challenging his authority, Worcester reminds him of the Percy family's role in helping Henry to the throne (making his power and greatness "portly"). Worcester's point is important. If the Percys helped Henry knock King Richard off the throne, they're certainly capable of bumping off King Henry as well. We know the Percys will lead the rebellion against the king later in the play, so Henry's got to find a way to maintain power and control of the crown.
But soft, I pray you; did King Richard then
Proclaim my brother Edmund Mortimer
Heir to the crown?
He did; myself did hear it. (1.3.6)
As we know, the legitimacy of Henry's kingship is debated throughout the play and has some important implications. Here, the Percys insist that Hotspur's brother-in-law, Mortimer, is the legitimate heir to the throne, not King Henry. So, not only did Henry usurp the crown, we're reminded that he's not the blood heir to the throne and there's another man who was named a successor.
Time for a history snack: Traditionally, the crown passes from father to son by lineal succession, which was thought to have been sanctioned by God. (This concept is also known as the doctrine of "divine right," which just says that kings can't be questioned by their subjects because they've been appointed by God to rule on earth. Challenging a divinely sanctioned king, then, is considered a major sin.) King Henry not only deposed King Richard II, he also imprisoned him and is responsible for his "mysterious" death, which makes his crime even worse. (This all goes down in Richard II, but there are plenty allusions to it in Henry IV Part 1. Check out our discussion of Henry's sense of guilt over the whole thing in "Warfare.")
Nay, then I cannot blame his cousin king,
That wished him on the barren mountains starve. (1.3.5)
We've just seen in the previous passage how the Percys claim Mortimer is the legitimate heir to the throne. This, says Hotspur, is why King Henry refuses to ransom Mortimer from the Welsh – as long as Mortimer is in Wales, he can't make a bid for the crown. Henry, of course, tells a much different story. He claims he won't ransom Mortimer from the Welsh because the earl is a traitor, one who married a Welsh woman (Glendower's daughter) and intentionally allowed English troops to be slaughtered by the Welsh army. So, who's telling the truth?
We notice a pattern in the play – we're often given multiple and incompatible accounts of the same events, which makes it kind of hard to take sides – it's never really clear who or what we should believe. On the one hand, the rebels make some valid points about King Henry – he has usurped the throne and he probably does want to keep Mortimer as far from England as possible. On the other hand, Henry's the king and whatever he says goes, right? But, it's hard to obey (or believe) a king whose own rebellion against Richard II has opened the door for more rebellion, against him.