The Merry Wives of Windsor is perhaps the only Shakespeare play to have evolved out of popular demand for a particular character. Sir John Falstaff first appears in Shakespeare's work in the history play Henry IV, Part One. In this play, he is the young Prince Hal's companion who aids the Prince's predilection for pranks, schemes, and diguises. He reprises his role in Henry IV, Part Two. Falstaff does not appear in Henry V, which details the reign of Prince Hal once he becomes king and puts aside the antics of his youth. In this play, characters discuss Falstaff's recent death and suggest that he was broken-hearted when Hal rejected him.
The Merry Wives of Windsor purportedly takes place some time between Henry IV, Part One and Henry IV, Part Two, when Falstaff still maintains his connection to the English throne. However, critics have long pointed out that the Windsor presented in the play is not, as one would expect, a depiction of the fourteenth century but instead resembles something much closer to early modern England itself. Within the timeline of the Henriad, this setting is of course impossible. However, many have noted that the English middle class – the social group depicted in the play – did not come into existence until Shakespeare's own lifetime.
Certainly, Shakespeare would have been aware of this discrepancy while writing The Merry Wives of Windsor, so it is rarely considered an error on the part of the playwright. Instead, Falstaff's appearance in what would have been contemporary England was likely an appeal to audiences who wanted to see more of Falstaff in a comedic setting rather than a serious history play. It seems as though Shakespeare decided to "freeze" Falstaff in time – at the height of his comedic potential, between the two Henry IV plays – and transport him to a much more recognizable landscape for his audience. Unfortunately, the play was criticized heavily during its early performances, and the anachronistic timeline could have contributed to this unpopularity.