helena seems to have followed her husband to gaul and is next reported being pregnant with his child. this pregnancy ended in a miscarriage. ammianus reports on further miscarriages: "meanwhile constantius' sister helena, wife of julian caesar, had been brought to rome under pretence of affection, but the reigning queen, eusebia, was plotting against her; she herself had been childless all her life, and by her wiles she coaxed helena to drink a rare potion, so that as often as she was with child she should have a miscarriage. for once before, in gaul, when she had borne a baby boy, she lost it through machination: a midwife had been bribed with a sum of money, and as soon as the child was born cut the umbilical cord more than was right, and so killed it; such great pains and so much thought were taken that this most valiant man might have no heir." in the historical study "ammianus marcellinus and the representation of historical reality" (1998) by timothy barnes, the birth of this stillborn son is estimated to 356. the miscarriage in rome to 357. barnes considers the story of the potion-induced miscarriages to be an allegation without further reference. gibbon had not completely dismissed the report:"even the fruits of his [julian's] marriage-bed were blasted by the jealous artifices of eusebia herself, who, on this occasion alone, seems to have been unmindful of the tenderness of her sex, and the generosity of her character" ... "for my own part i am inclined to hope that the public malignity imputed the effects of accident as the guilt of eusebia." he left the question of the existence of such a poison open and to be determined by physicians rather than historians. "a history of medicine" (1995) by plinio prioreschi dismisses the account as an example of a very common error in accounts of ancient medicine, "the attribution to drugs of properties that they could not have". in this case, a potion which is consumed just once and keeps having effect for years. prioreschi regards it as "an obvious impossibility in the light of modern pharmacology".