Can Kate Middleton get remarried if Prince William dies?

Answer 1

Legally she could - if Prince William died, she would have fulfilled her "contract" of "till death us do part" and would be free to remarry.

There are bound to be controversial or political issues were she to do so however. For example, if William died after they had had children, there might be an expectation that Kate should "do her duty" to mother the future monarch, without bringing in a new father figure who would have influence over a future king without a royal background of his own while the child was in infancy.

Henry VIII's sixth wife, Catherine Parr, remarried after his death.