Christian Saints

St. Margaret, one of the early saints, daughter of a pagan priest, was born in Antioch and converted into Christianity by her nurse. Later the Roman governor Olymbrius liked her, but was rejected because of her vow of chastity. She was put to prison, where the Devil attacked her, then a dragon swallowed. But she managed to cut his belly with a little crucifix and escape. Olymbrius ordered her to be tortured and finally she was beheaded. She is often depicted with crucifix or cross, dragon, pearl rosary.
See: Fra Bartolommeo The Annunciation, with Saints Margaret, Mary Magdalene, Paul, John the Baptist, Jerome and Francis.
Jean Fouquet. St. Marguerite.
Rogier van der Weyden St. Margaret and St. Apollonia.
Francisco de Zurbarán St. Margaret.

Recommended reading:
The Book of Saints: The Lives of the Saints According to the Liturgical Calendar by George Angelini, Victor Hoagland (Editor). Regina Press, Malhame & Company, 1986.
365 Saints: Your Daily Guide to the Wisdom and Wonder of Their Lives by Woodeene Koenig-Brick (Author). Harper SanFrancisco, 1995.
All Saints: Daily Reflections on Saints, Prophets, and Witnesses for Our Time by Robert Ellsberg. Crossroad/Herder & Herder, 1997.