daughter of Julius Constantius

A daughter of Julius Constantius and Galla, of unknown name, was Roman empress as the first wife of Constantius II.

Family She is mentioned in the "Letter To The Senate And People of Athens" by Emperor Julian to have been a sister of Constantius Gallus.

Gallus was a son of Julius Constantius and his first wife Galla. She is assumed to be a full sister of Gallus. The event is reported in the "History of the Arians" (358) by Athanasius of Alexandria, in a denunciation of Constantius II. "The common feelings of humanity could not induce him to spare even his own kindred… he commiserated not the sufferings of his father-in-law, though he had married his daughter…" Though Constantius had two later marriages, this is considered a reference to Julius Constantius.

A brother is considered to have been assassinated with their father in 337. Julian the Apostate was a younger, paternal half-brother to this Empress. The marriage can be estimated to 335 or 336.

Neither her name nor the time of her death appear in surviving sources. Thomas M. Banchich, a modern historian, points that "her passing may have facilitated Gallus' fall in 353/4".