[TOMT][BOOK][90’s/2000s]

Hi all, I can’t remember the name of this book and it’s annoying me as I would like to read it again. These are the details I remember: - it was part of a trilogy - it was a young adult novel - fantasy/adventure - main character is a teen/young adult princess, daughter of the king. Her mother, the queen isn’t around - can’t remember why. - the first book was a dark navy cover with a silver sword down the front vertically. - the last book involves her travelling a long distance to recruit armies for a big battle. I remember a clan from the desert rode zebras instead of horses - in the first book, I think she is exiled into the forest or runs away there - it would have been written in the late 90’s or early 2000’s.