Miriam is first introduced in The Thieves of Ostia, as the timid and kind sister of Jonathan. She is seen grieving over the death of her family's dog, Bobas.
In The Secrets of Vesuvius, Flavia Gemina's tutor, Aristo, and Vulcan, a blacksmith, fall for her beauty whilst she is staying on Gaius' farm and they both can't resist giving her love gifts. Miriam, however, pays no attention to them, for she has fallen deeply in love with Gaius. He loves her back, and they express their desire marry. Aristo and Vulcan are left distraught - especially the former, who takes to playing mournful music once home again. During the eruption of Mt. Vesuvius, Miriam and Gaius stay together the whole time and say that they would die for each other. They both survive.
Miriam continues her relationship with Gaius in The Assassins of Rome and, for a while, is happy and content. However, trouble arrives for her family when her uncle, Simeon ben Jonah, appears on their front doorstep. Simeon is a wanted assassin and being hunted down by the magistrate. His unexpected and unwanted arrival leads up to her brother's sudden disappearance and the arrest of her father. Miriam is left alone and therefore temporarily moves into Flavia's house. She stays there whilst the four detectives go off to find Jonathan and Simeon in Rome. When her family returns, she is overjoyed.
Miriam is a gentle young woman who shies away from conflict, but she will get angry if her any of her friends or family is hurt. She is also shown to have a strong will, particularly when she makes her father save her babies and not herself, much to his distress.
She is described as being extraordinarily beautiful, with pale skin, long, curly black hair and violet eyes.
Due to her stunning appearance, many men fall in love with her, which she resents. Men have fought over her and once there was a collision in the street when a man was distracted from the road by gaping at her. Therefore Miriam usually wears a veil or headscarf when out and about.
- Miriam is a female given name of Hebrew origin. The meaning is unclear, but is likely either "rebelliousness", "wished-for child", "bitter" or "strong waters".
- Miriam is a Christian, but a Jew by birth. This means that several Jews in her neighbourhood disapprove of her and her family.
Miriam is mentioned and appears in several of the books, including: