Jean-Robert Argand (1768-1822) was a Parisian bookkeeper. It is not known whether
he had mathematical training. Argand produced a pamphlet in 1806, run by a private
press in small print. He failed to include his name in the title page. The title was “Essay
on the Geometrical Interpretation of Imaginary Quantities”. One copy ended up in the
William Rowan Hamilton (1805-65) in an 1831 memoir defined ordered pairs of real num-
bers (a, b) to be a couple. He defined addition and multiplication of couples: