Who is Eusebia from Julian and what is their importance?

Eusebia was Constantius' wife. Though she's early on a supporter of Julian, she later shows that she's also worried about her own position in the royalty. Eusebia never produces an heir and the blame is laid clearly at the feet of her husband. Nonetheless, Eusebia doesn't want Julian's wife, Helena to produce an heir. She paid a midwife to kill the only child Helena delivered alive by cutting the umbilical cord too short. While Julian never speaks badly of Eusebia, Helena eventually shifts her loyalty to Julian because of Eusebia's actions. Helena is a proper wife to Julian, but is much older. She died of a tumor in her stomach. Her final words to her husband were of the need for new tiles on her beloved villa.