Even though it is very difficult to judge these things, this person has been widely called the wealthiest person in the history of the world. Ruler of an African nation, most of his riches came from the vast amount of gold and salt which were found in his land.
He became famous for his pilgrimage to Mecca in 1324 with reportedly 60,000 men and insane amounts of gold. He spent most of it on his way, building mosques, giving alms to the poor and buying souvenirs and ended up pumping so much money that he destabilized the economies of the region he went through. Infact this is the only time recorded in history that one man directly controlled the price of gold in the Mediterranean.
Identify this king of kings.