Algeria is the second largest country on the African continent.It is bordered by Tunisia in the northeast, Libya in the east, Niger in the southeast, Mali and Mauritania in the southwest, and Morocco as well as a few kilometres of the Western Sahara, in the west. Constitutionally, Algeria is defined as an Islamic, Arab, and Amazigh (Berber) country.Algeria is a member of the African Union; it is also a member of OPEC (Organisation of Petroleum Exporting Countries).*****************The name Algeria is derived from the name of the city of Algiers (French Alger), from the Arabic word al-jaza’ir, which translates as the islands, referring to the four islands which lay off the city's coast until becoming part of the mainland in 1525. Al-jaza’ir is itself a truncated form of the city's older name jaza’ir bani mazghanna, "the islands of (the tribe) Bani Mazghanna", used by early mediaeval geographers such as al-Idrisi and Yaqut al-Hamawi.***********Algeria has been inhabited by Berbers (or Imazighen) since at least 10,000 BC. After 100 BC, the Carthaginians began establishing settlements along the coast. The Berbers seized the opportunity offered by the Punic Wars to become independent of Carthage, and Berber kingdoms began to emerge, most notably Numidia. In 200 BC, however, they were once again taken over, this time by the Roman Republic. When the Western Roman Empire collapsed, Berbers became independent again in many areas, while the Vandals took control over other parts, where they remained until expelled by the generals of the Byzantine Emperor, Justinian I. The Byzantine Empire then retained a precarious grip on the east of the country until the coming of the Arabs in the 8th century.*************After some decades of fierce resistance under leaders such as Kusayla and Kahina, the Berbers adopted Islam en masse, but almost immediately expelled the banou moussa caliphate from Algeria, establishing an Ibadi state under the Rustamids. Having converted the Kutama of Kabylie to its cause, the Shia Fatimids overthrew the Rustamids, and conquered Egypt. They left Algeria and Tunisia to their Zirid vassals; when the latter rebelled and adopted Sunnism, they sent in a populous Arab tribe, the Banu Hilal, to weaken them, thus incidentally initiating the Arabisation of the countryside. The Almoravids and Almohads, Berber dynasties from the west founded by religious reformers, brought a period of relative peace and development; however, with the Almohads' collapse, Algeria became a battleground for their three successor states, the Algerian Zayyanids, Tunisian Hafsids, and Moroccan Marinids. In the fifteenth and sixteenth centuries, Spain started attacking and subsuming many coastal cities which prompted some to seek help from the Ottoman Empire.