I wonder what people's opinions are on which century was the most impressive in terms of how far mathematics leaped forward. What's your opinion? The 20th century with Grothendieck's impact on algebraic geometry, the Feit-Thompson Theorem, the Langland's Program, etc? The age of Fermat and Newton and Leibnitz? The 3rd century CE with Diophantus and Liu Hui?
I think the leap from about 1810 to 1910 was freaking astounding. Going from not even having a strong definition of continuity and having very scant development of abstract algebra (permutation groups mostly), then ending up with Abel-Ruffini and Galoi Theory, Cayley's impact on abstract algebra, Hilbert with his Nullstellensatz (and a million other things), Weierstrass completely upending analysis, Cauchy and Riemann beefing up complex analysis, the initial development of Fourier series, and ending with the Lebesgue integral.
What do y'all think?