John D Rockefeller, who was the richest person in US history when he died in 1937, made his fortune from Standard Oil a precursor of ExxonMobil. Photograph: Jessica Rinaldi/Reuters John D Rockefeller, who was the richest person in US history when he died in 1937, made his fortune from Standard Oil a precursor of ExxonMobil. Photograph: Jessica Rinaldi/Reuters