Carl Jacobi

As a young unknown whose work made advances on their own, Jacobi wrote to Gauss and Legendre; both were strongly impressed. He met Legendre in Paris (also Fourier and Poisson), and visited Gauss along the way. Jacobi, recovering from a breakdown, and his close lifelong friend Dirichlet led a posse of mathematician friends (Steiner, Jacobi’s former student Borchardt, with Schläfli as interpreter), on a long recuperative visit to Italy; Humboldt made it financially possible. Hesse was another student, Neumann and Bessel colleagues in Könbigsberg, while Hamilton and Babbage were met in Manchester.