The earliest slave trade was across the Sahara. Slaves were brought up the Niger River to Timbuktu and transported across the Sahara into North Africa. Which of the following was necessary before large numbers of slaves could be moved across the desert?

Before large numbers of slaves could be moved across the Sahara, the following factors were necessary:

1. Development of trade routes: Trade routes needed to be established and well-established across the Sahara to facilitate the movement of goods, including slaves.
2. Access to water sources: Caravans traversing the desert required access to water sources at regular intervals to sustain themselves and the slaves. Wells, oases, or other water sources were crucial for survival during the arduous desert journey.
3. Technological advancements: The use of camels and the development of camel caravansary systems allowed for the transportation of larger numbers of slaves across the desert. Camels could withstand the harsh desert conditions and carry heavy loads, making them an efficient means of transport.
4. Political stability: Stable empires or states were needed to ensure the protection of the trade routes and caravans crossing the Sahara. With political stability, there was reduced risk of raids or attacks on the slave trade and caravans.
5. Demand for slaves: There needed to be a demand for slaves in North Africa or other regions accessible through the Sahara trade routes. The presence of markets and buyers willing to purchase slaves incentivized the transport of large numbers of slaves across the desert.