Blood and Sand by CV Wyk 

Roma Victrix. The Republic of Rome is on a relentless march to create an empire―an empire built on the backs of the conquered, brought back to Rome as slaves. Attia was once destined to rule as the queen and swordmaiden of Thrace, the greatest warrior kingdom the world had seen since Sparta. Now she is a slave, given to Xanthus, the Champion of Rome, as a sign of his master’s favor. Enslaved as a child, Xanthus is the preeminent gladiator of his generation… Read more.