What is the author's style in The Constant Princess by Philippa Gregory?

The book is written in an easy-to-read style with a story line that flows adequately through the lifetime of Catalina, Infanta of Spain. There are a few instances in which words of that time period are used that might not be familiar to all readers. In most cases, the meanings are not obscure and a reader with an adequate vocabulary will have no trouble reading and understanding the book.