After the conquest was completed, the Romans gathered the indigenous peoples into jurisdictions, each with a Roman center of administration and justice. Olissipo (present-day Lisbon-- Lisboa in Portuguese), served as the administrative center of Roman Portugal until the founding of Emerita (present-day Mérida, Spain) in A.D. 25. By the beginning of the first century A.D., Romanization was well underway in southern Portugal. A senate was established at Ebora (present-day Évora) schools of Greek and Latin were opened industries such as brick making, tile making, and iron smelting were developed military roads and bridges were built to connect administrative centers and monuments, such as the Temple of Diana in Évora, were erected. Gradually, Roman civilization was extended to northern Portugal, as well. The Lusitanians were forced out of their hilltop fortifications and settled in bottom lands in Roman towns (citânias).

The citânias were one of the most important institutions imposed on Lusitania during the Roman occupation. It was in the citânias that the Lusitanians acquired Roman civilization: they learned Latin, the lingua franca of the peninsula and the basis of modern Portuguese they were introduced to Roman administration and religion and in the third century, when Rome converted to Christianity, so did the Lusitanians. All in all, the Roman occupation left a profound cultural, economic, and administrative imprint on the entire Iberian Peninsula that remains to the present day.

Data as of January 1993