Fantasy of Frost question

Hi! Sorry this is not about "Fantasy Frost", i had to put a title in. I read this fantasy book in 2007, but cant remeber the name or author. I do remeber the cover was red with a gold crown, maybe a sword. There was a sequel with a blue cover too. I dont remember much of the plot except it starts off at a home for boys and a knight shows up and takes one. The sequel mostly took place in the dessert. The word "king" may have been in the title too. Any thought help, thanx!