Place and date of birth

She was born in Constantinople after the flight of her mother Galla to Thessoloniki to escape from usurper Maximus, together with her Mother Justina and brother Valentian II. Valentian II was official emperor of the West. Mother Justina introduced Galla to emperor of the East Theodosius who was recently widowed. They married in the early spring of 387.
Galla never left Constantinople while Theodosius went to battle against from 388-391.
The first-born was Gratian (388) who died young, the second was Galla Placidia (May/ June 389 or 392/393) and the last was John (394) who died at birth together with Galla.