Administratively, the municipality is divided into 4 civil parishes (freguesias):[3] Proença-a-Nova traces its origins to Roman times when it was called Cortiçada in the province of the Lusitani.

Cortiçada perhaps related to the abundant production of cork oak (cortiça) or the number of tenement houses (colmeias) that had been of great importance in the region.

Until the date of its first charter, by Afonso III, little is known about the village of Proença but it is believed that farming the low, fertile, well irrigated lands and hunting the abundant wildlife were the most important ways of subsistence.

The population was primitive until being given to the Monks of the Order of the Hospitallers, who collaborated with the first Kings to stabilise and defend the new lands.

In 1244, the Prior of the Hospitallers, Frei Rodrigo Egídio, gave Proenca its first charter, a document of great importance establishing the general duties for its inhabitants and a guarantee of defense of rights.