Where did the west African kingdoms get many of the first slaves?

Timbuktu, the capital city, became a leading Islamic center for education, commerce, and the slave trade.

Explanation:

It appears there was a slave-trade route through the Sahara that brought sub-Saharan Africans to Rome, a global center of slavery.

Resistance to lifetime servitude began with the first Africans forcibly brought to the Western Hemisphere in the 1500s, and resistance continued until the last emancipations in the Americas.

your answer is rising unemployment and inflation.