Elon Musk's rise to become the world's first trillionaire has revived interest in a question that once captivated an earlier generation: who was the first billionaire and, before that, the first millionaire?

It took more than a century to go from first millionaire to first billionaire, and another century to hit $200 billion. Now the world is waiting for its first trillionaire.

There is new money, old money, and then the kind of money that could make someone the world's first trillionaire!

At a time when concerns about inequality are high and public attitudes toward the ultra-wealthy have soured, Musk has managed to retain a loyal following despite his…