In The Tale Of Despereaux, Miggery Sow has been made a servant at the castle after a soldier informs Uncle that the law no longer allows anyone in the Kingdom of Dor to own a slave. One day, Louise, the head of the serving staff, tasks Miggery Sow with running an errand. She is to deliver a spool of red thread to the princess. However, when Miggery meets the princess, she is so excited at seeing the princess that she drops the spool of thread, slips, and loses her balance. After she picks herself up, she attempts to curtsey to the princess before she presents her with the thread.
Miggery is curious as to why the princess would need a spool of red thread. The princess tells her that she is making a tapestry of the history of her father's kingdom. On the tapestry, she points out to Miggery her father playing a guitar and her mother eating soup. The princess and Miggery Sow both discover that their mothers are dead and that they are both twelve years old. Later on, Louise tells Miggery that she took too long to run the errand and gives her a clout to the ear.
Thanks for the question!