Collaboration in the writing of plays was not uncommon during the late sixteenth century and the early seventeenth century, e.g. the names of Francis
Beaumont and John Fletcher appear as co-authors of a number of plays. Much
research has been carried out into the language and content of the plays
of the period resulting in the assumption that many collaborations went
unrecorded. The Shakespeare plays have also been analyzed and it has been
proposed that a number of these plays were authored by more than one person.
It is therefore probably not surprising that there is a group theory relating to authorship of the Shakespeare plays. Francis Bacon, Edward de Vere, Roger Manners and Mary Sidney Herbert have all been considered as members of groups who authored the plays. In addition to these and other members of the aristocracy, professional playwrights of the day such as Christopher Marlowe, Robert Greene and Thomas Nashe have been proposed as co-authors of the Shakespeare plays.