Delighted to learn about 18th-century King Gustav III of Sweden. Intent on proving the harmful effects of tea and coffee, he commuted the death sentences of identical twins to life imprisonment, if one of them would drink 3 pots of coffee every day for the rest of his life, and the other the same amount of tea.
The tea-drinking twin died at 83, long after the king's death by assassination. No one knows when the coffee-drinking twin died, because both doctors monitoring him died before him.