Given a factoid/trivia type question, generate the topic of the question. The topic is the entity the question talks about.

In which wars did the battles of Towton and Barnet take place?
battle of barnet

And Another Thing... by Eoin Colfer, published in 2009, eight years after the death of the author of the first five, is described as the sixth in which trilogy of books?
and another thing...

Princess Estelle, Duchess of Ostergotland, granddaughter to King Carl XVI Gustaf, became 2nd in line to what nation's throne when born in 2012?

carl xvi gustaf of sweden