Cush occupied a strategic location south of Egypt, controlling the cataracts of the Nile: Because the cataracts are barriers to river transportation, whoever controlled them also controlled the important caravan routes that went around them. Cush’s capital, Kerma, lay between the third and fourth cataracts. A garrison of Jewish mercenary soldiers, brought to Egypt to help defend the southern border with Cush, was established on Elephantine Island in about 650 B.C.E. This provided some of the main points of contact between Hebrews and Cushites.