Prince Freya Series by Keiko Ishihara

Freya thinks of herself as a simple village girl, but her idyllic life is shattered when she is caught up in a treacherous Sigurdian plot. She bears a striking resemblance to her country’s Prince Edvard, who lies dying from poison. Without its prince, Tyr will quickly be engulfed by violence. Now Freya must take Prince Edvard’s place and lead his valiant knights in defending the realm!

Freya finds her charade as Prince Edvard difficult to maintain as she battles her own crushing grief and treacherous Tyrish nobles. With the help of her dear friend Alek and her new guardian Sir Julius, however, she’s determined not to give up. But will her new resolve and impulsive nature send her straight into the jaws of danger?!

Freya is determined to help the soldiers trapped in the besieged Fort Leren, but with reinforcements days away, the only thing she has to offer them is her presence and everything it represents. But how can she embody the Prince of Hope when she is consumed by anger?

The unexpected arrival of horned warriors at Fort Leren is all that saves the Tyrish troops from the Sigurdian seige. But the Kelds have no interest in joining forces with Tyr—they only intervened to cause pain to their old foe. While it is a disappointing decision, it opens Freya’s eyes to other paths of resistance. Tyr might have no allies, but Sigurd has many enemies!

Freya has been granted Tyr’s royal jewel and the chance to seek allies in the fight against Sigurd. But the journey to hope is fraught with danger, and Freya and her knights will have to survive a voyage across a pirate-infested sea before they can even begin to secure the help her kingdom needs!