'Sister Queens' retells a familiar story in a completely fresh way. It's a gripping tale of love, of sacrifice, of the demands of duty, and of the conflict between ambition and loyalty. Katherine (better known as Katherine of Aragon, Henry VIII's first queen) and Juana, daughters of Ferdinand and Isabella of Spain, were sister queens. While their royal birth conferred entry into a world of privilege and plenty, as it did for their two siblings, Isabella and Maria, it came with a devastating personal price-tag. Since monarchs operated within an international as well as a domestic setting, it was inevitable that Ferdinand and Isabella would use their children as dynastic pawns, but daughters, unlike sons, were expendable. They might be happy, they might not. It was largely a matter of chance. Isabella and Maria, married to Portuguese princes, both died young and far from home. And when they too were sent as brides to foreign shores, Katherine and Juana were to need all their courage, resolve and inner strength as they faced the harsh realities of life in a male-dominated world.