As a young student at the Ecole Polytechnique, I attracted the attention of both Lagrange and Laplace.
I was a devout Catholic and a political reactionary who openly defended the Jesuit order during the 1830 revolution, even leaving Paris in protest when Charles X was forced into exile.
I was very prolific as an author of 789 mathematical papers, being second only to Euler in total output.
I basically created the idea of determinants, though I viewed them as a system of alternating symmetric functions.
Finally, perhaps symptomatic of my "cranky" attitude towards others, I was a leader in promoting rigor in the development of calculus notions (e.g. the convergence of series).
Augustin-Louis Cauchy (1789-1867)