At the end of the 19th, Georges d'Avenel produced a highly original work in various fields. Unsatisfied with the usual way to write history, he turned his attention to quantitative data to understand the past. In particular, he built series of prices of multiples goods and services from 1200 onwards. He proposed a documented analysis of long-term changes in prices as a result of the technical progress, in income and wealth inequalities as captured by the top 1%, as well as in the evolution of mentalities. His approaches were criticized both by both new professional "Republican" historians than by Conservative analysts. However, his data used by Pareto, Fisher, Frisch or Marshall are still used in current economic history and his analysis fertilized various fields in particular the Ecole des Annales.