St. Emerentiana was a Roman martyr, who lived around the start of the 4th century. Emerentiana’s mother was the nanny of St. Agnes, so is cosidered the foster sister of St. Agnes.
A few days after Agnes’ death, Emerentiana, who was a catechumen still learning about Christianity before being officially baptized, went to the tomb to pray and was suddenly attacked by the pagans, stoned to death by the crowd. She is represented as a young girl who either has stones in her lap and lilies in her hand, or as being stoned to death by a mob.