When Alexander the Great usurped the Persian Empire he acquired an immense amount of gold in hundreds of thousands of "talents", don't know the current equivalent, but it was an immense amount.
He used it to finance his empire and successors' empires. His funeral procession was made mostly of golden items. It could have been a sight to see, but only a few saw it.
The wealthiest man is not easy to identify except the definition of wealth is given. However, am still of the opinion that the wealthiest is the person with heart of love, good family, sound health and satisfactory. A greedy man never satisfy even as Billionaire.
The ancient king of present day Mali who controlled the flow of gold into Europe and Islam from Timbuctoo. So rich he controlled the economies of the Middle Ages' states around him.
Mansa (/Emperor) Musa Keita or Musa I of Mali (c. 1280 - c. 1337), a 14th century African emperor of the Mali Empire.
A Muslim emperor and a successful military leader.
Jeff Bezos the current richest man in the world is worth US$150 billion.
Mansa Musa's net worth adjusted to today's value is roughly US$400 billion.
The source of his wealth was his land's vast amounts of natural resources particularly, gold.
His wealth became known to the world in 1324 during his pilgrimage to Mecca. During this journey, he caused mass inflation in Cairo by spending so much gold on the poor.
Word of his wealth spread across the Mediterranean. He is included on the 1375 Catalan Atlas.
He built the legendary Djinguereber Mosque in Timbuktu, which still stands today.
Huffingtonpost - Mansa Musa Of Mali Named World’s Richest Man Of All Time; Gates And Buffet Also Make List
@ Nicolai Nypan is correct that it can be hard to separate wealth from power. I would look for an absolute ruler of a large geographic region having an abundance of natural resources and a large population, wherein there may be nominal private property, but ultimately everything is really owned by the ruler, even the populace, who would have slave-commodity value. Queen Victoria wouldn't qualify, but maybe one of the Chinese emperors?
Alexander the Great who inherited the immense gold reserves of the Persian Empire (gold originated in the mines of today's Tajikistan, Uzbekistan, Turkmenistan and Kyrgyzstan - in the so- called "Tien Shan Gold Belt" and has the world's biggest gold mines.