Different versions of Shakespeare's plays exist, as they circulated in unauthorised copies, known as "bad quartos", put together from shorthand notes taken during the performance of from memorial reconstruction by the actors of the company.
Good and bad quartos depended on the closeness to the original manuscript.
The canon was essentially established with the publication of Shakespeare's works in the First Folio edition of 1623 by John Hemingford and Henry Connel, actors and collaborators of Shakespeare. The First Folio includes 36 plays which are divided into three sections: comedies, histories and tragedies. 18 of the 36 plays were printed for the first time, while the other 18 had already been printed in quarti editions.
Very little is known about the chronology of Shakespeare's plays, as they were not printed in the order of composition, but rather grouped by genre, Therefore, dating the plays depends on different kinds of documentary evidence.
Palladio Tania, a teatrise by Francis Meres which registered the plays performed.
Reference to contemporary events or to plays literary sources which gave evidence that a play could not have been written before that event or the composition of that literary work, as well as the staging of a play shoes that it could not have been written after that date.
Literary evidence provided by stylistic aspects common to Shakespeare's plays.