Alcácer do Sal () is a municipality in Portugal, located in Setúbal District. The population in 2011 was 13,046, in an area of 1499.87 km2. History Earliest settlement There has been human settlement in the area for more than 40,000 years; archaeological investigations have placed human presence here back to the Mesolithic Period, when the first peoples began to concentrate in the areas around Alcácer. This period was characterized by exploitation of the ecosystem in the Sado Estuary, when the river extended to São Romão, involving fishing, scavenging for shellfish, hunting and foraging in the local forests. The primitive tools, made from chert, were adapted from the techniques of the late Paleolithic era. By the late Mesolithic period, people had concentrated in the area of Comporta and Torrão, later establishing primitive defensive protection to support its communities. These principal settlements were abandoned by the Copper Age, but repopulated during the Iron Age, as was the case of Alcácer. Mediterranean trade, pioneered by the Phoenicians, introduced commercial colonies in Abul and Alcácer (then referred to as Bevipo or Keition), where a written alphabet and currency allowed commerce to flourish. Roman Era After the Third Punic War, with the fall of Carthage, Alcácer was annexed to the Roman Empire (around 1st-2nd century B.C.). The municipality of present Alcácer became known as Urbs Imperatoria Salacia in honor of the sea god Neptune's wife, nymph Salacia, for its importance in the Iberian salt trade and the number of routes that crossed the area. In the third century the port of Salacia fell into disuse thanks to the emergence of Olisipo (Lisbon). With the rise of Gaul, most of Hispania became a vassal state of the larger empire. Returning to the Imperial fold with the 296AD reorganization of Roman territories by Diocletian (in order to subvert the Military Anarchy that existed at the time), Salatia's role was transformed. Circa 300? it was the seat of a Diocese of Salácia (Portuguese) / Salacien(sis) (Latin) / Salarien(sis) (Latin), which was however suppressed around 350. In the following centuries, Salatia became a poor distant colony of the much larger centers of Setúbal or Lisbon. The only exception was Torrão, which continued to prosper. Until 711, when the region was annexed by the Umayyad Caliphate of Damascus, the population of the hilltop areas of Salatia left in favor of the low lands along the river. Al-Andalus The Ummayad rule