It has been widely argued that Boisguillebert
had the idea of general equilibrium as early as
around 1700. However, I do not know if he used
the actual word "equilibre" or some close equivalent
or not. Nor can I say exactly where in his writings
does one find the clearest statement that has led
some to make the claim about him and the GE concept,
which he may have been the first to enunciate in
some form or other.
Barkley Rosser