who was the first billionaire

The first billionaire in history was John D. Rockefeller. He officially became the world's first billionaire by 1916 through his immense fortune earned as the founder of Standard Oil, which monopolized much of the oil industry in the United States. Rockefeller's wealth at the time was estimated to be around 2% of the U.S. GDP, making him the wealthiest person of his era and the first to amass a net worth over one billion dollars. Beyond business, he is also known for his extensive philanthropy, including founding the Rockefeller Foundation and funding institutions like the University of Chicago.