The main plot of The Winter's Tale is taken from Robert Greene's pastoral romance Pandosto, published in 1588. Shakespeare's changes to the plot are uncharacteristically slight, especially in light of the romance's undramatic nature, and Shakespeare's fidelity to it gives The Winter's Tale its most distinctive feature: the sixteen-year gap between the third and fourth acts.
There are minor changes in names, places, and minor plot details, but the largest changes lie in the survival and reconciliation of Hermione and Leontes (Greene's Pandosto) at the end of the play. The character equivalent to Hermione in Pandosto dies after being accused of adultery, while Leontes' equivalent looks back upon his deeds (including an incestuous fondness for his daughter) and slays himself. The survival of Hermione, while presumably intended to create the last scene's coup de théâtre involving the statue, creates a distinctive thematic divergence from Pandosto. Greene follows the usual ethos of Hellenistic romance, in which the return of a lost prince or princess restores order and provides a sense of closure that evokes Providence's control. Shakespeare, by contrast, sets in the foreground the restoration of the older, indeed aged, generation, in the reunion of Leontes and Hermione. Leontes not only lives, but seems to insist on the happy ending of the play.
It has been suggested that the use of a pastoral romance from the 1590s indicates that at the end of his career, Shakespeare felt a renewed interest in the dramatic contexts of his youth. Minor influences also suggest such an interest. As in Pericles, he uses a chorus to advance the action in the manner of the naive dramatic tradition; the use of a bear in the scene on the Bohemian seashore is almost certainly indebted to Mucedorus, a chivalric romance revived at court around 1610.
Eric Ives, the biographer of Anne Boleyn (1986), believes that the play is really a parallel of the fall of the queen, who was beheaded on false charges of adultery on the orders of her husband Henry VIII in 1536. There are numerous parallels between the two stories – including the fact that one of Henry's closest friends, Sir Henry Norreys, was beheaded as one of Anne's supposed lovers and he refused to confess in order to save his life claiming that everyone knew the Queen was innocent. If this theory is followed then Perdita becomes a dramatic presentation of Anne's only daughter, Queen Elizabeth I. Referring to more recent events, Edward Chaney suggested that Robert Greene when writing Pandesto may have had in mind Earl of Oxford's suspicions about the paternity of his daughter (granddaughter of Lord Burghley) when he returned in 1576 from his continental tour that may have included Sicily.