6 Blacks who claimed freedom then earned exponential wealth as slave owners Statue of a child slave (Photo credit: Shutterstock / elyn) Contrary to popular opinion, slavery was not singularly unique to the United States and North America. Over the centuries it has been carried out on six of the seven continents. During the 13th century, the Mongols enslaved millions and frequently sold them in markets across Eurasia. Mansa Musa, King of the Mali Empire in the 14th century and considered to be the richest man to have ever existed, owned slaves and took more than 12,000 with him on his pilgrimage to Mecca. He became extremely wealthy selling Africans as slaves. Slavery was also widespread in many West and Central African societies before and during the trans-Atlantic slave trade. A true historical understanding of history in terms of U.S. slavery must acknowledge the fact many Blacks owned slaves from the time of the revolutionary war until the ratification of the 13th and 14th amendments.