Emperor Augustus established there a colony of his veterans and the city started to grow soon in importance. Augustus even founded -in what is now coastal Algeria- the following Roman colonies: Igilgili, Saldae, Tubusuctu, Rusazu, Rusguniae, Zuccabar, Thuburnica and Gunugu. All these colonies were connected to Aquae Calidae in a military way with strong commercial links.
The importance of Aquae Calidae -as the name indicated- was from the warm waters (reaching nearly 50 C.) that were used for the local famous roman thermae
During the centuries of Roman domination Aquae Calidae was a small but rich city with a Forum, theater, baths, library and aqueducts, but nearly all has disappeared. Only a necropolis of the city walls has shown the abundance of evidences about Aquae Calidae Christian past.
Occupied by the Vandals in the fifth century and damaged, the city was recovered to "Romanitas" by the Byzantines and regained importance during the sixth century.
Conquered by Arabs around 700 AD, Aquae Calidae nearly disappeared in the next two centuries.