The Portuguese territory has attracted man since the most remote times. Only with the Lusitanians, probably derived from an Iberian group settled in the mountainous areas of Beira and who, coming from NE, invaded the country in the first millennium BC. C., however, there was a first cultural homogenization of the country (not for nothing Lusitanian became synonymous with Portuguese over time), which materialized with the Roman conquest. The Romans were responsible for the creation of the first urban nuclei, located – unlike the perched mountain sites of the Lusitanian population – at the base of the hills or near the sea, the construction of an imposing road system, the introduction of vines and the extension of the cereal growing, which led to a more stable population in the lowland areas, previously used as areas of transhumance pastoral care for the people of the mountains; over time the coast became the vital part of the country. The Germanic invasions left no notable footprints in Portuguese history; The Arab domination, on the other hand, was decisive, introducing in the southern areas and along the coast the mainly irrigated crops of citrus fruits, olives and vegetables, animating commercial and urban life; Arab elements remained in the cities and countryside even after the invasion was repulsed. With the reconquest (11th-13th centuries) by the Northern Lusitans, the formation of the present Portuguese nation originated; the contact with the more advanced regions of the South gave the new State a notable impulse in every field of social and economic life, transforming the pastoral and agrarian civilization of the North into a primarily mercantile civilization. The first demographic data date back to 1527, the year in which 1.1 million residents were estimated; since then Lisbon, capital of the largest empire in the world, e Port, known for its trade with northern Europe, especially with England (close ties with Great Britain have always been one of the cornerstones of Portuguese foreign policy), were the two major centers of the country. With the advent of the great sea voyages there was a massive exodus of population to the New World, naturally especially to Brazil, and Portugal suffered a real depopulation for two centuries.
Even the demographic pressure recorded since the nineteenth century has been constantly reduced by a strong migratory movement, which in several years has exceeded 100,000 expatriates with a prevalent flow no longer to America but to France, Great Britain, Germany and, in the past, towards the African possessions. Starting from the mid-seventies of the century. XX this outflow was partly balanced by almost one million returns from the African colonial territories that had achieved independence. Internal mobility is also intense, in particular the major cities attract workers: Lisbon absorbs residents from the Center and the South, Porto from the North. According to iamhigher, the population of Portugal remained substantially stable in the 1990s thanks to the progressive balancing of migratory flows and the natural demographic movement. As a consequence of its past as a colonial power, Portugal presents an ethnic framework in which, in addition to the Portuguese (96%), Brazilians and other minor groups find space. The urbanization rate, traditionally much lower than the European average, rose to 64.7% in 2017, while the population density (111.43 inhab. / km²) is fairly high when compared to that of other European countries. Lisbon, whose metropolitan area has over 3 million residents, continues to represent the country’s largest demographic, economic and cultural pole. Located on the Douro is Porto, the Roman Portus Cale, whose name is linked to the importance of the port itself, both for the intense commercial activity that takes place, both for the excellent wine production, and for the conspicuous industries, especially textiles. AS of Lisbon, at the mouth of the Sado, is Setúbal, a very busy port and commercial center. Among the cities of the interior, which arose as a function of agricultural activity, few have developed; among these of considerable importance is Coimbra, located on the right bank of the Mondego, in the heart of a fertile rural area, one of the major tourist and cultural centers of the country. Finally, on a hill overlooking the fertile Minho plain, there is Braga, a traditional agricultural market and now home to mechanical, textile and food industries.
The particular morphology of the country determines irregular and fast watercourses through steps and steep gorges of erosion; they flow into the sea with long estuaries in which the tidal current penetrates deeply (for about seventy km into the Tagus), transforming them into good communication routes: above all the Tagus (more precisely, in Portuguese, Tejo), on whose estuary it does not by chance Lisbon arose, it is almost entirely navigable, and the Douro for 2/3 of its course. In the Portuguese territory the great Iberian rivers have the final stretch of their course, in particular, in addition to the Tagus, the Douro (in Spanish Duero) and the Guadiana, which, however, mainly concern Spain where they originate; The rivers that have their basin entirely in Portugal, on the other hand, are scarce and of modest development, the main ones being the Mondego which cuts through the Beira and the Sado, which collects the waters of most of the southern regions. Given their rain-fed feeding, they all have a very irregular regime, with very strong differences in flow rate over the course of the year; in fact, they present considerable floods during the rainy season (when overflows with often disastrous consequences are not rare) with maximums in January or February, while their flow significantly decreases during the summer drought period: the Mondego has a winter flow even 3000 times higher than the summer one.