Benjamin Franklin bequeathed £1,000 (about $4,400 at the time, or about $115,000 in 2019 dollars) each to the cities of Boston and Philadelphia, in trust to gather interest for 200 years.
The trust began in 1785 when the French mathematician Charles-Joseph Mathon de la Cour, who admired Franklin greatly, wrote a friendly parody of Franklin’s Poor Richard’s Almanack called Fortunate Richard. The main character leaves a smallish amount of money in his will, five lots of 100 livres, to collect interest over one, two, three, four or five full centuries, with the resulting astronomical sums to be spent on impossibly elaborate utopian projects.
Franklin, who was 79 years old at the time, wrote thanking him for a great idea and telling him that he had decided to leave a bequest of 1,000 pounds each to his native Boston and his adopted Philadelphia.