Question regarding Shakespeare's co-authors

Hi,
In the below extract I would like to know if the following people mentioned were Shakespeare’s collaborators or simply authors working independently on “Sir Thomas More”.It’s not very clear to me.

Anthony Munday
Henry Chettle
Thomas Heywood
Thomas Dekker

I look forward to your feedback.
davidmich
http://en.allexperts.com/q/Shakespeare-3004/2013/3/shakespeare-co-authors.htm

"In the case of the play called Sir Thomas More , although we can’t be absolutely certain that Shakespeare had any hand in it, it’s generally accepted nowadays that Anthony Munday wrote the original play, which was then revised in some places by Henry Chettle. Some time later, the play was thoroughly revised by a team of playwrights who we think were Thomas Heywood, Thomas Dekker, William Shakespeare, and some as-yet-unidentified person. "

Sir Thomas More exists in manuscript – it was never printed and, probably, never staged. (As a play about a Catholic martyr, it would have been inflammatory material in Protestant England – although the play is purposefully vague about exactly why More was executed, and the notes on the manuscript by Edmund Tilney, the Master of the Revels and de facto state censor, suggest that Tilney was doing his best to make it playable.)

Anyway, the text is kind of a mess – in addition to the original version of the play, which is in a single hand that is probably Munday’s, there are a host of additions, notes, and cancellations showing the handwriting of at least five more people, in addition to Tilney. Most scholars think that Munday wrote out the copy of the original version of the play, which he had either written entirely by himself or in collaboration with some other playwrights, and then at a later date several other playwrights got called in to do some collaborative script-doctoring and retouching. This may have happened in response to Tilney’s comments, although since they don’t actually comply with everything Tilney told them to do, this isn’t at all clear. (Tilney, for example, tells them to leave out a scene of popular rebellion, which instead shows evidence of revision rather than deletion.) It’s also possible that they predate the submission of the play to Tilney, or that the play was submitted more than once and revised in between.

Anyway, we’re pretty confident that two of the five hands responsible for the handwritten editions are Chettle and Dekker; a third seems to be a scribe; the fourth and fifth are less confidently identified as Heywood and Shakespeare. We also don’t know for sure whether they were writing in collaboration, or whether they were working on the manuscript (in sequence or concurrently) without consulting each other.

“We also don’t know for sure whether they were writing in collaboration, or whether they were working on the manuscript (in sequence or concurrently) without consulting each other.”

Thanks FretfulPorpentine for that clarification.
davidmich

The majority of scholars accept that Hand D in the manuscript is Shakespeare’s. The quality of the verse suddenly rises into the stratosphere and the effect is as great as in another collaborative play, Pericles, at the commencement of Act III in which the hairs rise on the base of the reader’s neck and one is acutely aware that William has entered the building.

I was very surprised to learn (from the book The Lodger Shakespeare by Charles Nicholl ) that Shakespeare undoubtedly collaborated in the cases of The Two Noble Kinsmen and Pericles. I knew that he was thought to have co-writers in the case of Sir Thomas More from my reading, but not that the potential list was so long.
Someone on another message board had this to say about More:

http://en.allexperts.com/q/Shakespeare-3004/2013/3/shakespeare-co-authors.htm

I didn’t know about his potential authorship of Edward III. Live and learn.