To add context to this, I ran a calculation of simple interest and compound interest you'd receive for an initial investment of £4.31 over the 294 years from 17

To add context to this, I ran a calculation of simple interest and compound interest you'd receive for an initial investment of £4.31 over the 294 years from 1720 to today. I assumed a 3% return. Simple interest, not reinvested: £42.32 Compount interest: £25,622.49 As the parent poster pointed out, the actual return for a bond bought in 1720 depends on what the holder did with the returns. Whereas with gold, merely holding £4.31 worth of gold from 1720 would yield £768 of gold today. I found this calculation interesting in that it demonstrates the true power of compound interest if maintained. Of course, such a return is actually very hard to maintain over a 300 century timespan.