A Reader of Taste may easily observe, that tho' Shakespeare, almost in every Scene of his historical Plays, commits the grossest Offences against Chronology, History, and Ancient Politicks; yet This was not thro' Ignorance, as is generally supposed, but thro' the too powerful Blaze of his Imagination; which, when once raised, made all acquired Knowledge vanish and disappear before it. For Instance, in his Timon, he turns Athens, which was a perfect Democracy, into an Aristocracy; while he ridiculously gives a Senator the Power of banishing Alcibiades. On the contrary, in Coriolanus, he makes Rome, which at that time was a perfect Aristocracy, a Democracy full as ridiculously, by making the People choose Coriolanus Consul: Whereas, in Fact, it was not till the Time of Manlius Torquatus, that the People had a Right of choosing one Consul. But this Licence in him, as I have said, must not be imputed to Ignorance: since as often we may find him, when Occasion serves, reasoning up to the Truth of History; and throwing out Sentiments as justly adapted to the Circumstances of his Subject, as to the Dignity of his Characters, or Dictates of Nature in general.

In his Historical Plays, whenever our English Chronicles, and in his Tragedies when Greek or Roman Story, could give any Light; no Pains have been omitted to set Passages right by comparing my Author with his Originals: for, as I have frequently observed, he was a close and accurate Copier where-ever his Fable was founded on History.
Lewis Theobald
Preface to the Works of Shakespeare (1734)