Shakespeare's King Lear exists in two significantly different versions, the quarto (Q) published in 1608 and the folio (F) of 1623. Scholars typically believe that the play was altered for performances after its first printing. Possibly this took place around 1610, when the King's Men were interested enough in the legendary history of Britain to perform Cymbeline. The folio text was the seeming product of these revisions.
Distinctive features of Q include a more elaborate mock trial; the pathos of servants helping the blinded Gloucester; and a more substantial denunciation of Goneril by Albany. By contrast, Albany is systematically demonised in F (including having his final speech reassigned to Edgar); F has the Fool's famous prophecy; and F consistently politicises the action in a way not found in Q. The Folio text justifies Lear's decision to divide the kingdom between the dukes ('while we / Unburthen'd crawle toward death') somewhat more than Q, and it amplifies the uncomfortable exchange of 'nothings' between Lear and Cordelia. Perhaps most interestingly, Lear dies differently in Q and F. He has a moment of delusion in F ('Do you see this? Looke on her? Looke her lips, / Looke there, looke there ...') before dying, causing Kent so much pain that he wishes his own heart would break. In the quarto, Lear wills his own heart to break, and then expires.