During the 19th century French Revolution, a young French boy Evariste Galois self-studied Math and invented a totally strange math called “Group Theory“, in his own saying –
“A new Math not on calculation but on reasoning“.
With Group, Galois proved a 300-year-old problem that Quintic equations with degree 5 (or more) have no radical solution (ie formula using +, -, ×, ÷, nth root). During his short tragic life (21 years) his work was not understood by the world masters like Cauchy, Fourier, Poisson, Gauss, Jacobi…
“Group Theory” is the foundation of Modern Math today.