Who is the historical fiction author of a book about Richard the Lionhearted?

[Debater]

I read this book awhile back. He was portrayed has having relations with a boy who turns out to not be a boy. I think the author was a woman. She wrote other books as well. One about Eleanor of Aquitaine (sorry if that's not spelt right) and another about Henry VII. They were written in first person point of view.