Fausta

Flavia Maxima Fausta was a Roman Empress, daughter of the Roman Emperor Maximianus. To seal the alliance between them for control of the Tetrarchy, in 307 Maximianus married her to Constantine I, who set aside his wife Minervina in her favour. Constantine and Fausta had been betrothed since 293.

Her sons became Roman Emperors Constantine II, reigned 337 340, Constantius II reigned 337 361, and Constans reigned 337 350. She also bore three daughters Constantina, Helena and Fausta. Of these, Constantina married her cousins, firstly Hannibalianus and secondly Constantius Gallus, and Helena married Emperor Julian. Apparently a genealogical claim that her daughter Fausta became mother of Emperor Valentinian I is without foundation .

Source: Wikipedia