This is the story of the most turbulent period of the Roman Empire told from the point of view Linia, the personal slave of the daughter of an immigrant tavern-keeper, Elena. Elena meets a young officer and eventually marries him, bearing his son Constantine. She supports her husband through his rise to be Caesar of the Western empire. He then divorces her. She is unable to bear more children, but brings up her son to honor his father and his father's religious preference, Sol Invicta - the Unvanquished Sun. The idea of a single god for the whole empire takes root. Elena herself becomes a secret Christian, partly as a result of having to watch martyrs suffering. When her son is held hostage by pagans in the East, she plans his escape to join his father in England. When his father dies, Constantine assumes his father's imperial role and Elena joins him. She supports him as he fights to capture Rome, persuading him that the "one god" who guides him is the Christian God. His ambition to rule both halves of the empire leads him on, while Elena succeeds in her persuasion. When the whole empire is conquered, Elena is styled Empress Helena and works to build basilicas from Trier to Jerusalem. In her old age her son's increasing paranoia results in murders within his own household. Helena goes on pilgrimage to Jerusalem in expiation, and returns having discovered the true cross, but worn out herself. Constantine promises before she dies that he will be baptized as a Christian, but not until his death-bed. The book deals with life in the Roman Empire - slavery, religious persecution, illegal immigration, subjugation of women, martyrdom, rape as a weapon of war, and the quiet growth of Christianity ("like bread dough - the more you press it down, the bigger it grows"). Saint Helena is revered as the discoverer of the true cross, while her son claims credit for converting the Empire. The reader must judge.