Act III. [A heath.] The storm and king rage: the moment of greatest dramatic tension in King Lear comes precisely at the center of the play and remains the work’s fulcrum, yet where did Shakespeare get the idea for it? We have dozens of possible sources for Lear, yet none seems to yield sufficient clue. Lightning flashes twice in Shakespeare’s most certain source, The True Chronicle Historie of King Leir and His Three Daughters (?1594; 1605), where it frightens the messenger who is sent by Ragan to murder Leir and Perillus in the thicket, but the lightning is seen there by the three men as a sign of heavenly judgement, as flashes of cosmic omen, not as a raging storm within the broader kingdom or the little mind of man. Another likely source for Shakespeare, Book II, chapter 10 of Sir Philip Sidney’s Arcadia (1590), provided the playwright with a foul storm which allows Sidney to tell the story of the Paphlagonian king overheard by Pyrocles and Musidorus and now accepted as the basis for the subplot of Gloucester, Edmund, and Edgar. Sidney’s single Ciceronian sentence elongates the effectiveness of his description.