A German tale.  When the queen dies, a witch works her way into the king's life.  She is jeleous of his four children and so want to get rid of them.  The king shows them a secret place that can only be reached by following the unraveling of a migical ball of yarn.  When the queen finds the yarn, she arrives at the secret place.  She turns the three boys into ravens but the princess escapes.  The ravens tell the princess that she can break the curse on the by saying no word for three years three months and three days.  Later she gets married, still saying nothing, a finds that her new mother in law is the witch - married to a new king.  When she has children, they mysteriously disappear.  She is accused of being witch and set to burn at the stake three years three months and three days after her vow of silence.