Sword and Tempest — Michael Mounts

The Sword Maiden Princess journeys to Sparta, and just in time to be pressed into service. Sparta is at war with the entire Achaean League, and the Tyrant of Sparta insists on the Gentle Stepper herself leading the armies of Sparta. Just to help her along, he hands off his troublesome daughter into the custody of that same Gentle Stepper. The phalanx forms, the cavalry rides, and the Gentle Stepper is there, always in the middle of melee.