Saint Marcellina (c. 327 – 397) was born in Trier, Gaul the daughter of the Praetorian prefect of Gaul, and older sister of Saint Ambrose of Milan. She devoted her life to the practice of prayer and asceticism. Her feast day is July 17.
Marcellina was born in Trier, Gaul around the year 330 as a member of a Catholic family. Her father served as Praetorian prefect of Gaul. The sister of Ambrose of Milan, she was older than her two brothers. while still young, she traveled to the family home in Rome, and devoted herself to the practice of piety and asceticism. On Christmas Day, probably in 353, she received the veil of consecrated virginity from Pope Liberius.
As the eldest sister in her family, she made it a point to pass her younger brothers the "desire not to express their virtue, but to become truly virtuous." This life she led call for continual abstinence, dedication to prayer, strict fasting, etc. This life chosen by Saint Marcellina is one of great sacrifice.
After Ambrose had become Bishop of Milan in 374, he summoned his sister, and found in her a zealous assistant in fostering and extending the ascetic life among the maidens of Milan. Marcellina survived her brother by a year, dying in 398. Honored as a saint, she was buried in the crypt under the altar of the Ambrosian Basilica in Milan.
Marcellina was one of the few female Christian leaders in 2nd-century Rome. She came originally from Alexandria, where she learned of Carpocrates. Her movement has been characterized as Gnostic, denying all the worldly laws. The group was most active and influential in the 150s and 160s. They shared everything, including partners, and they displayed images of Greek philosophers alongside icons of Christ.Irenaeus complained in his treatise Against Heresies that Marcellina led the masses down the wrong path. Her supporters branded themselves with a small mark on the back of their right ear.