North Africa was for a long time part of a world that was separated from the rest of the African continent. Wedged between the Sahara Desert and the Mediterranean Sea, it inevitably looked to the north rather than to the south. To the east its fertile coast was so narrow that in places the desert reached the sea but the coast broadened in the west to include cultivable plains and there were mountains separating it from the desert. Climatically, North Africa belonged with the Mediterranean, with hot dry summers and mild winters when most of the modest rainfall occurred. Culturally, the region formed a meeting place for the peoples of the Levant, Greece and Rome with those of North Africa. As such it played a role in the history of Europe as well as of Africa. Each was to influence the other and the common link was the Mediterranean Sea, providing relatively easy movement for traders and migrants and a frequent focus for armed conflict. A number of sea-oriented colonial settlements grew up in North Africa between about 2800 and 1300 years ago, resulting in complex interaction with the indigenous inhabitants and the development of distinctive literate communities. Towards the end of the period Christianity was widely adopted but was subsequently overwhelmed by Islam, following invasion of the region by Arab people (Chapter 16).