A zero in mathematics! --------------------------
A brilliant student, gifted in both science and the humanities, Henri Poincaré earned his baccalauréat ès lettres with a Bien grade in August 1871. Three (very studious) months later, he sat the baccalauréat ès sciences. But in one of the written mathematics papers, he scored... zero!
Gaston Darboux recounts: "Strangely enough, he came close to failing—and failing because of the mathematics paper. Apparently, he had arrived late and misunderstood the question. Fortunately, he had already made something of a name for himself. "Any other student, the chair of the examining board said as he announced the names of those allowed to proceed, would have failed because of his mathematics paper." Needless to say, he redeemed himself brilliantly in the oral examination; he passed with an Assez bien grade."
The Poincaré "style" ---------------------
"In the thesis he submitted to the Faculty of Paris in 1878 for a doctorate in mathematical sciences, he tackled a difficult question [...]: the integration of partial differential equations with any number of independent variables."