to draw large crowds. There were also aesthetic reasons: Renaissance aesthetic theory took seriously the dictum that tragic plots should be grounded in history. For example, King Lear is probably an adaptation of an older play, King Leir, and the Henriad probably derived from The Famous Victories of Henry V. There is speculation that Hamlet (c. 1601) may be a reworking of an older, lost play (the so-called Ur-Hamlet), but the number of lost plays from this time period makes it impossible to determine that relationship with certainty. (The Ur-Hamlet may in fact have been Shakespeare's, and was just an earlier and subsequently discarded version.) For plays on historical subjects, Shakespeare relied heavily on two principal texts. Most of the Roman and Greek plays are based on Plutarch's Parallel Lives (from the 1579 English translation by Sir Thomas North), and the English history plays are indebted to Raphael Holinshed's 1587 Chronicles. This structure did not apply to comedy, and those of Shakespeare's plays for which no clear source has been established, such as Love's Labour's Lost and The Tempest, are comedies. Even these plays, however, rely heavily on generic commonplaces. While there is much dispute about the exact chronology of Shakespeare's plays, there is a general consensus that stylistic groupings largely reflect a chronology of three-phases: Histories and comedies – Shakespeare's earliest plays tended to be adaptations of other playwrights' works and employed blank verse and little variation in rhythm. However, after the plague forced Shakespeare and his company of actors to leave London for periods between 1592 and 1594, Shakespeare began to use rhymed couplets in his plays, along with more dramatic dialogue. These elements showed up in The Taming of the Shrew and A Midsummer Night's Dream. Almost all of the plays written after the plague hit London are comedies, perhaps reflecting the public's desire at the time for light-hearted fare. Other comedies from Shakespeare during this period include Much Ado About Nothing, The Merry Wives of Windsor and As You Like It. Tragedies – Beginning in 1599 with Julius Caesar, for the next few years, Shakespeare would produce his most famous dramas, including Macbeth, Hamlet, and King Lear. The plays of this period address issues such as betrayal, murder, lust, power and egoism. Late romances – These plays romances, including Pericles, Prince of Tyre, Cymbeline, The Winter's Tale and The Tempest, are so called because they bear