Did You Know? Augustus Caesar was the wealthiest man to ever live in history. He was the nephew and heir of Julius Caesar, the Roman Emperor. Augustus had an estimated net worth of $.46 trillion when counting for inflation. Some others may say that Mansa Musa, king of Timbuktu, was the world’s wealthiest man as his wealth was apparently too great to count. However, Augustus’s staggering wealth could actually be measured.