The Lot-et Garonne has more of these medieval " new towns " than any other French department, a total of forty of the five hundred that have been identified.
The Bastides represented an urban revolution, which began in the 13th century and whose significance we can best determine by looking at their historical and geographical context.
At the beginning of the Middle Ages, the local countryside was mostly wooded and only Agen, which covered about 10 hectares, qualified as a town. The population lived in scattered, cultivated clearings and a few groups of dwellings or hamlets of ancient origin were situated close to commercial trade routes.
The feudal system began in the 10th century in response to a general economic and demographic expansion. Royal authority was divided up among a multitude of minor lords, who administered land farmed by serfs working as unpaid vassals. For reasons of safety (and the lord's profit), dwellings gradually gathered around the lord's castle to form castle villages (Pujols, Penne d'Agenais and Castelnaud-de-Gratecambe are examples). Similar gatherings were found around churches or abbeys, taking advantage of the sanctuary afforded by God's protection, (for example Sauveterre St.Denis and la Sauvetat-de-Savères).
In both cases a lay or religious lord assembled and controlled a previously dispersed working population in order to clear the surrounding land and bring it under cultivation.
These two organisations were the precursors of the major urban planning movement, the last of the Middle Ages, which was to be the creation of the Bastides.