This play begins with Polixenes' visit to Leontes and Hermione, to demonstrate the history that these two men share. As the Enotes character analysis of Polixenes says so well:
The two kings have been friends since childhood, Polixenes fondly remembering that childhood as one of carefree innocence as yet untempered by the realities of the world. The two were then indistinguishable in their innocence and energy. Polixenes reminds Leontes, "We were as twinn'd lambs that did frisk i' the sun / And bleat the one at th' other" (I.ii.66-67).
This sameness that they share is important in the play, because it sets up, from the beginning, the notion that every man is fallible and susceptible to acting in regrettable ways. For Leontes, this irrationally reprehensible behavior consumes the first part of the play through his accusations that his wife and best friend have been having an affair, an accusation that drives Polixenes to flee for home and leads to Leontes killing his son, banishing his baby daughter to be abandoned for dead, and, he believes, killing his wife.
For Polixenes, the irrational and reprehensible behavior comes when the play moves to Bohemia. He goes ballistic when he believes that his son has chosen a poor, shepherd's daughter for his wife. Unbeknownst to Polixenes, this shepherdess, Perdita, is the right daughter of Hermione and Leontes.
It takes the magic and grace of the final moments of the play, which includes the reconciling engagement of Florizel and Perdita, to bring healing and forgiveness to Leontes and his friend, the man who has also acted reprehensibly, Polixenes.
Both men share a similar journey of self-awareness and the two journeys reflect upon each other to strengthen the overall message of the play. It is this connection as a sort of "mirror image" to Leontes that gives Polixenes his importance as a character and also gives meaning to his journey as a reflection of that of Leontes.
i think all the characters in winter,s tales are important as every character made actions which affected the play as mary and charles lamb summarrized the plays writing the important characters and the important events.
polixenes has great importance intheplay as if he was not found leontes would no suspect that his dearest friend was un faithful to him and at the end of the play he refused the marriage of his son from perdita so they went to sicily to leontes, and she found her father,but comparing the 2 characters leontes is more important as without
thinking with jealousy and cruelity the play hasn,t any events and tragedy so i think that he was the main character in the play.