James Smithson was the illegitimate child born to the Duke of Northumberland and Elizabeth Keate Macie in 1765. He could never assume a royal title. In 1786 he graduated from Pembroke College, Oxford, and became a fellow of the Royal Society with his proficiency in chemistry and minerology. His work includes 27 published papers, 200 manuscripts, and thousands of notes.
Smithson wrote his will at the age of 61. In it, he arranges a pension for a former servant, and leaves the rest of his estate to his nephew. At his nephew's death, the money is to go to the nephew's heirs, or, if there are no heirs, to the United States, to establish a "Smithsonian Institution."
Smithson died in Genoa in 1829. His nephew lived only another 6 years after Smithson, and died without heirs. His death began the arduous process to accept the bequest, get the money, and decide how to use it.