What Commodities Were Traded Across The Sahara?

What commodities were traded across the Sahara? Why were gold and salt the most important trade items?
Some commodities were gold, ivory, salt, cloth, and even slaves. North Africa had salt and South Africa had gold, so they would trade, and Ghana was in between so it would control the trade. Salt was important because everyone needed it, it was the only way to preserve food. Salt was so important that it was even “worth it’s weight in gold.” Gold was important because it was used for money.

How was agriculture preformed in the Sudan? What difficulties did the farmers there face? Why would there be a division of labour between men and women?
In the Sahel, some people farmed crops but most people were herders. More in the south, farming was