Curan's report of strife between Albany and Cornwall helps illustrate that Lear's division of his kingdom is a mistake. Shakespeare's Elizabethan audience would have expected such a conflict since the English know, all too well, that insurrection and conflict between petty lords requires a strong centralized government to maintain control. Making Cornwall and Albany equal, in effect co-leaders, inevitably leads to discord. Curan's disclosure is, at this moment, unimportant, except that Edmund sees the information as useful to his plotting.
Edmund, an opportunist, takes advantage of Curan's report and accelerates his plans by calling Edgar out of hiding and creating a mock battle. By self-inflicting a minor wound, Edmund makes Edgar look like a villain. Gloucester is fooled easily by the staged sounds and blood of battle. With the physical evidence before his eyes, Gloucester believes Edmund's story.
Edmund also convinces his father of Edgar's attack by carefully selecting his words:
Spoke with how manifold and strong a bond
The child was bound to th' father; Sir in fine,
Seeing how loathly opposite I stood
To his unnatural purpose, in fell motion,
With his prepared sword he charges home
My unprovided body, launch'd arm. (II.1.46–51)
