The Talisman of Troy by Valerio Manfredi

A castaway tossed onto a deserted beach is the last survivor of a world that no longer exists. He has a terrible, fascinating story to tell – the true reason for which the Trojan War was fought… The protagonist of this tale is Diomedes, the last of the great ancient Greek Homeric heroes, who seeks to return to his beloved homeland after years of war against Troy. But destiny has other plans for him. Betrayed by his wife, who plots to murder him and persecuted by hostile gods, he has no choice but to turn his sails west, towards Hesperia, the mysterious mist-shrouded land that will one day be called Italy. He ventures boldly into this new world, for he carries with him the magic Talisman of Troy, a mysterious, powerful idol that can make the nation that possesses it invincible…