In the 2nd century BC, from the early times of the Roman period, the existence of Caldes thermal waters encouraged the start of significant thermal spa activity that led to the formation of a small town centre around it.

This centre, called Aquae Calidae (hot waters), became the centre of a Roman municipality of Latin law in the 1st century BC. This event implies that, aside from the thermal spas and related amenities, Caldes was also an administrative, religious, economic and commercial centre.