Portuguese people are a Romance ethnic group indigenous to Portugal that share a common Portuguese culture, ancestry and speak Portuguese. Their predominant religion is Christianity, mainly Roman Catholicism, though vast segments of the population, especially the younger generations, have no religious affiliation. Historically, the Portuguese people's heritage largely derives from the pre-Celts and Celts (Lusitanians, Gallaecians, Turduli and Celtici), who became culturally Romanized during the conquest of the region by the ancient Romans. A number of Portuguese can also trace minor descent from Germanic tribes who arrived after the Roman period as ruling elites, including the Suebi, Hasdingi, Visigoths and Buri in northern Portugal and central Portugal. Finally, there were also limited conversions of Jews and Berbers as a result of the Moorish occupation of the Iberian Peninsula, especially in the Algarve region of southern Portugal.