Publication of Théorie des fonctions analytiques

Background. By the mid-1790s Lagrange was firmly established in Parisian scientific life. He had become the first professor of analysis at the École Polytechnique upon its opening in 1794, and in 1795 he was appointed to a mathematical chair at the short-lived École Normale, where Fourier was among those attending his lectures.

Publication of the Treatise. Lagrange's lectures on the differential calculus at the École Polytechnique formed the basis of his treatise Théorie des fonctions analytiques, published in 1797. The work laid some of the foundations of group theory, anticipating Galois. His lectures at the school also yielded a further publication, the Résolution des équations numériques of 1798.