Exxon, Mobil, Chevron, Amoco and ARCO trace back to Standard Oil
The 1911 Standard Oil breakup split Rockefeller's trust into 34 companies, and five of them grew into Exxon, Mobil, Chevron, Amoco and ARCO
We haven't written up this one. Quartz has the full story — the link below goes straight to it.