King Edward IV is the same as the King Edward of Henry VI, Part Three, who won his throne by battle.
He is much older now, and very ill. He is incurably optimistic and hopes to be able to reconcile all of the warring factions of his court, but at the same time is suspicious and superstitious enough to imprison his brother Clarence on the word of the fortune-teller. (Considering how easily Clarence betrays people – see Henry VI, Part Three – this is not necessarily foolish on his part.) His marrying a penniless widow and raising her brothers and sons to the nobility incensed many of his followers (see Henry VI Part Three) and they have still not calmed down, despite the King’s best efforts. He still enjoys the company of women, and keeps a mistress fairly openly. Though he signs a death warrant for his brother, he rescinds the order; the shock of hearing that it has been carried out shocks him to his core and brings on his death.