Minna's Quest: Roman Pony Adventures (Unabridged Fiction‪)‬

Minna is just a blacksmith's daughter, yet she succeeds in raising a sickly abandoned foal, turning him into the pride of the Roman cavalry. Her stubborn determination and fiery nature burn brightly in the quiet fort of Othana and soon attract the secret admiration of the proud commander Theo.
But even Theo cannot imagine the part Minna and her beloved horse will play when Othana is threatened by bloodthirsty pirates. Desperate to save her people, Minna risks all as she set out on a perilous journey over land and wave to fetch help.