After the prehistory of Volume I, Volume II of The Cambridge History of Africa deals with the beginnings of history. It is about 500 B.C. that historical sources begin to embrace all Africa north of the Sahara and, by the end of the period, documentation is also beginning to appear for parts of sub-Saharan Africa. North of the Sahara, this situation arises since Africans were sharing in the major civilizations of the Mediterranean world. It is shown that these northern Africans were not simply passive recipients of Phoenician, Greek, Roman and Arab influences, or of the great religions and cultures of Judaism, Christianity and Islam coming from the Semitic world. They adapted these things to their own particular needs and purposes, and sometimes too contributed to their general development. But the North African civilization failed to make headway south of the Sahara. The agricultural crops that sustained it were unsuited to the tropics: the growth of populations large enough to secure effective mobilization of resources therefore depended on the development of new crops by Sudanic cultivators immediately south of the Sahara. When this had been done, the foundations were laid for a wholly African civilization and, by the end of the period, the Bantu expansion had brought almost all the southern half of the continent within its sphere.