In an older question about the purpose of the prologue in Romeo and Juliet, Cory Howell asked in a now deleted answer:
For what it's worth, the Prologue is not included in the First Folio version of Romeo and Juliet. So one must wonder, was it traditional to omit the Prologue by the time the First Folio was printed in 1623?
Shakespeare's First Folio contained 36 plays, 18 of which had been published before in quarto format. There are differences between the quarto and folio versions of the reprinted plays and sometimes these are considerable. If the quarto version contained a prologue, was it traditional to omit it in the First Folio edition?