(FORTUNE Magazine) – Lots of companies on the FORTUNE 500 have history, but only one dates back to 1784. That's the year Alexander Hamilton, then 27, founded the Bank of New York. In the 220 intervening years the bank has undergone more than nine name changes and over 100 mergers and acquisitions, but has held one continuous charter, making it the oldest company on the 500.

British ships were barely out of New York Harbor when Hamilton, already a Revolutionary War hero and an author of The Federalist Papers, penned the bank's constitution. BNY made the first loan to the U.S. government ($200,000 in 1789); it was the first business listed on the New York Stock Exchange (1792); and it also financed the Erie Canal. Today BNY is the 13th-largest commercial bank in the U.S. (Anyone calling the bank's headquarters gets a reminder of its history: the number is 212-495-1784.)

Of course BNY didn't appear on the 500 until service companies were included in 1995. So what's the oldest industrial company? That would be DuPont, which was founded by Eleuthere Irenee (E.I.) du Pont, an explosives expert and Huguenot who fled persecution during the French Revolution and set up shop in the U.S. in 1802. DuPont joined the first 500 and has been on every single list since. --Abrahm Lustgarten