History of human migration

Human migration, being the movement by people from one place to another with the intention of settling temporarily or permanently in the new location, typically involves movements over long distances and from one country or region to another.

Migration can be voluntary or involuntary. Involuntary migration includes the slave trade, trafficking in human beings and ethnic cleansing.

Historical migration of human populations begins with the movement of Homo erectus out of Africa across Eurasia about 1.75 million years ago. Homo sapiens appear to have occupied all of Africa about 150,000 years ago, moved out of Africa 70,000 years ago, and had spread across Australia, Asia and Europe by 40,000 years BCE. Migration to the Americas took place 20,000 to 15,000 years ago. Nonetheless, by 2,000 years ago, most of the Pacific Islands were colonized. Later population movements notably include the Neolithic Revolution, Indo-European expansion, and the Early Medieval Great Migrations including Turkic expansion. In some places, substantial cultural transformation occurred following the migration of relatively small elite populations, Turkey and Azerbaijan being such examples. In Britain, it is considered that the Roman and Norman conquests were similar examples, while "the most hotly debated of all the British cultural transitions is the role of migration in the relatively sudden and drastic change from Romano-Britain to Anglo-Saxon Britain", which may be explained by a possible "substantial migration of Anglo-Saxon Y chromosomes into Central England (contributing 50%–100% to the gene pool at that time.)"

...
Wikipedia