The Mark of Cain by Darlene Mindrup
Christian historical (loosely) romance. This story is based in the early period after the formation of the Christian church, when persecution was rife and the Romans ruled. Mara was born with a birthmark, which was believed to be a sign of evil or a family seriously screwing up and getting a long lasting punishment. She and her grandmother are accordingly shunned, and they struggle in poverty until Mara attracts the attention of a wealthy landowner who happens to be a member of the followers of Christ-at the time considered a dangerous fringe group.