It depends on what you consider wealth as, do you mean gold and silver and diamonds ? Diamond is most valuable of the of gems and that would make India most wealthy as it was the only source of that for most part of the history. But value is only relative, may be diamond would be considered worthless in ancient china and just some shiny stone and nothing else.

Persian empire can be considered wealthiest in terms of manpower, size and output during B.C era

Sorry, we don't allow throughout history questions. These tend to produce threads which are collections of trivia, not the in-depth discussions about a particular topic we're looking for. If you have a specific question about a historical event or period or person, please feel free to re-compose your question and submit it again. Alternatively, you may PM /u/caffarelli to have your question considered for an upcoming Tuesday Trivia thread.