Stone tools, some dating as far back as 280,000 BC, have been found in Adrar Bous, Bilma and Djado in the northern Agadez Region.[21] Some of these finds have been linked with the Aterian and Mousterian tool cultures of the Middle Paleolithic period, which flourished in northern Africa circa 90,000 BC??0,000 BC.[22][21] It is thought that these humans lived a hunter-gatherer lifestyle.[21] During the prehistoric African humid period, the climate of the Sahara was wetter and more fertile, a phenomenon archaeologists refer to as the "Green Sahara", which provided "favourable" conditions for hunting and later agriculture and livestock herding.[23][24] The Neolithic era, beginning circa 10,000 BC, saw a number of changes such as the introduction of pottery (as evidenced at Tagalagal, Temet and Tin Ouffadene), the spread of cattle husbandry, and the burying of the dead in stone tumuli.[21] As the climate changed in the period 4000??800 BC the Sahara gradually began drying out, forcing a change in settlement patterns to the south and east.[25] Agriculture spread, including the planting of millet and sorghum, and pottery production.[21] Iron and copper items appear in this era, with finds including those at Azawagh, Takedda, Marendet and the Termit Massif.[26][27][28] The Kiffian (circa 8000??000 BC) and later Tenerian (circa 5000??500 BC) cultures, centred on Adrar Bous and Gobero where skeletons have been uncovered, flourished during this period.[29][30][31][32][33] Societies continued to grow with regional differentiation in agricultural and funerary practices. A culture of this period is the Bura culture (circa 200??300 AD) named for the Bura archaeological site where a burial replete with iron and ceramic statuettes were discovered.[34] The Neolithic era saw the flourishing of Saharan rock art, including in the Aïr Mountains, Termit Massif, Djado Plateau, Iwelene, Arakao, Tamakon, Tzerzait, Iferouane, Mammanet and Dabous; the art spans the period from 10,000 BC to 100 AD and depicts a range of subjects, from the varied fauna of the landscape to depictions of spear-carrying figures dubbed 'Libyan warriors'.[35][36][37] Empires and kingdoms in pre-colonial Niger By at least the 5th century BC the territory of what is now Niger had become an area of trans-Saharan trade. Led by Tuareg tribes from the north, camels were used as a means of transportation through what is later a desert.[38][39] This mobility which would continue in waves for centuries was accompanied with further migration to the south and intermixing between sub-Saharan African and North African populations, and the spread of Islam.[40] It was aided by the Muslim conquest of the Maghreb in the 7th century, the result of three Arab invasions, which resulted in population movements to the south.[25] Empires and kingdoms existed in the Sahel during this era. The following adopts a roughly chronological account of some empires. Mali Empire (1200s??400s) Main article: Mali Empire The Mali Empire was a Mandinka empire founded by Sundiata Keita (r. 1230??255) in c.??230 and existed until the 1600s. As detailed in the Epic of Sundiata, Mali emerged as a breakaway region of the Sosso Empire which itself had split from the earlier Ghana Empire. Thereafter Mali defeated the Sosso at the Battle of Kirina in 1235 and then Ghana in 1240.[41][42] From its heartland around the later Guinea-Mali border region, the empire expanded under successive kings and came to dominate the Trans-Saharan trade routes, reaching its greatest extent during the rule of Mansa Musa (r. 1312??337).[citation needed] At this point parts of what are now Niger's Tillabéri Region fell under Malian rule.[41] A Muslim, Mansa Musa performed the hajj in 1324??5 and encouraged the spread of Islam in the empire, and it "appears that most ordinary citizens continued to maintain their traditional animist beliefs instead of or alongside the new religion".[41][43] The empire began "declining" in the 15th century due to a combination of internecine strife over the royal succession, weak kings, the shift of European trade routes to the coast, and rebellions in the empire's periphery by Mossi, Wolof, Tuareg and Songhai peoples.[43] A rump Mali kingdom continued to exist until the 1600s.[citation needed] Songhai Empire (1000s??591) Map of the Songhai Empire, overlaid over modern boundaries Main article: Songhai Empire The Songhai Empire was named for its main ethnic group, the Songhai or Sonrai, and was centred on the bend of the Niger River in Mali. Songhai began settling this region from the 7th to 9th centuries;[citation needed] by the 11th century Gao (capital of the former Kingdom of Gao) had become the empire's capital.[44][45] From 1000 to 1325, the Songhai Empire managed to maintain peace with the Mali Empire, its neighbour to the west. In 1325 Songhai was conquered by Mali until regaining its independence in 1375.[citation needed] Under king Sonni Ali (r. 1464??492) Songhai adopted an expansionist policy which reached its apogee during the reign of Askia Mohammad I (r. 1493??528); at this point the empire had expanded from its Niger-bend heartland, including to the east where most of later western Niger fell under its rule, including Agadez which was conquered in 1496.[21][46][47] The empire was unable to withstand repeated attacks from the Saadi dynasty of Morocco and was decisively defeated at the Battle of Tondibi in 1591; it then collapsed into a number of smaller kingdoms.[45] Sultanate of Aïr (1400s??906) The Grand Mosque of Agadez Main article: Sultanate of Aïr In c.??449 in the north of what is now Niger, the Sultanate of Aïr was founded by Sultan Ilisawan, based in Agadez.[21] Formerly a trading post inhabited by a mixture of Hausa and Tuaregs, it grew as a strategic position on the Trans-Saharan trade routes. In 1515, Aïr was conquered by Songhai, remaining a part of that empire until its collapse in 1591.[21][40] In the following centuries, it "seems that the sultanate entered a decline" marked by internecine wars and clan conflicts.[40] When Europeans began exploring the region in the 19th century, most of Agadez lay in ruins and was taken over by the French (see below).[21][40] Kanem?