Augustin-louis Cauchy
Mathematician
Pioneer in mathematical analysis who basically founded complex analysis singlehandedly, formulated and proved theorems in infinitesimal calculus, and rejected early mathematicians belief in the heuristic principal.
He studied civil engineering at Ecole des Ponts et Chaussees and landed a job as a junior engineer right out of college.
He dabbled in abstract algebra which led to the beginnings of permutation groups.
He married Aloise de Bure in 1818.
He was a mathematician just like Aleksandr Lyapunov.