King Lear opens with a conversation between the earls of Kent and Gloucester, in which the audience learns that Gloucester has two sons: Edgar, who is his legitimate heir, and Edmund, his younger illegitimate son. This information will provide the secondary or subplot. Next, King Lear enters to state that he intends to remove himself from life's duties and concerns. Pointing at a map, Lear tells those in attendance that he has divided his kingdom into three shares, to be parceled out to his three daughters, as determined by their protestations of love. The two elder daughters, Goneril and Regan, exaggerate their love by telling their father that their affection for him exceeds all reasonable expectations. The youngest daughter, Cordelia, tells Lear that she loves him, but only as a daughter should love a father. Lear, angry and disappointed at what he deems a lack of devotion on Cordelia's part, divides his kingdom equally between Goneril and Regan, and banishes Cordelia. Later, France agrees to marry the now dowerless and banished Cordelia. When Kent attempts to defend Cordelia, Lear banishes him as well. Meanwhile, Goneril and Regan decide that if Lear becomes too much of a nuisance, they will have to decide what disciplinary actions to take.
In the developing subplot, Edmund complains of his unhappiness at being an illegitimate — and thus, disinherited — son. As part of his plot to claim what is not his, Edmund gives a false letter to his father, Gloucester, declaring that Edgar is proposing that they kill their father and split the wealth between them. The cunning Edmund easily convinces his father that Edgar cannot be trusted.
Within a short time, Lear moves to Goneril's palace. Goneril tells Lear that he needs a smaller troop, more decorous in behavior and better suited to the king's rank and age. The king is very angry and says he will pack up his people and move to Regan's palace. Lear's anger continues to build, and he calls upon nature to curse Goneril's womb. In response, Goneril turns out 50 of Lear's retinue.
