Priestess of Avalon
Marion Zimmer Bradley
 As a young woman, the British priestess Eilan, known to the Romans as Helena, falls in love with the charismatic Roman Constantius. The Roman noble takes her away from Avalon as she is banished for this forbidden love and, before long, Helen bears him a son, who will become Constantine the Great. Helen's position in Roman society now gives her the freedom to travel about in the empire. When her son Constantine becomes Emperor, she slowly discovers brand-new roles. She faces the spread of the new Christian religion and seeks to understand the old knowledge of the goddess in light of the new religion. As Empress-Mother, Helena travels on a pilgrimage to the Holy Land to find the answers to questions that arise between the old religion and the new.