Who is Cornwall in Shakespeare's King Lear?

The Duke of Cornwall is a minor character in this
excellent tragedy and is Regan's husband in the play. Obviously he has profited greatly
from the half given to Regan of Lear's kingdom. However, he shows himself to be a
ruthless and greedy character. When he discovers the presence of the French in England,
he senses that his wealth and land is threatened and single-mindedly attempts to
discover everything he can about French intentions and whether they are aided by any
English. His thoughts of treachery are spurred on by the letter that Edmund shows to
Cornwall. Cornwall of course at this point shows his true, savage nature, bringing in
Gloucester to be tortured for what he knows about this letter, having his eyes gouged
out. The evident enjoyment that Cornwall takes in this process creates one of the most
disturbing and chilling scenes in all of Shakespeare, as Cornwall gouges out first one
then the other eye of Gloucester on stage:

readability="5">

Fellows, hold the
chair.

Upon these eyes of thine I'll set my
foot.

As he gouges out the
second eye, he says, "Out, vile jelly!" Clearly the way in which Cornwall tortures
Gloucester displays his true savage and evil nature. So outraged by his master's
behaviour, one of Cornwall's servants challenges him and wounds him
mortally.