Léon Joulin (1838–1928), was director of an explosives firm, Poudrerie de Toulouse. In addition to his professional activities, Joulin was responsible for extensive archaeological investigations in the region. Between 1897 and 1899, with the approval of the Société archéologique du Midi de la France, of which he was a corresponding member, he reopened the study of the site of Chiragan (Martres-Tolosane). Breaking with the conclusions of his predecessors, he scientifically proved that it was the site of a single, vast villa. Between 1900 and 1903, he helped explore Gallic sites in the Toulouse region. A gallery in the Musée du Vieux-Toulouse is named after him.
Even though villas had been systematically explored in Germany and in Belgium starting in the late 19th century, the Chiragan excavation remained an isolated case in France for more than half a century. The results, which were published in 1901, laid the foundation for a consistent excavation method for exploring and mapping a site that extended across more than 15 hectares. Taking a stratigraphic approach, Léon Joulin was able to date the villa, and he distinguished its various elements, thanks to excavations that included the villa's outbuildings. Reflections on the estate and how it operated, and an essay on its population and grain production reveal Joulin's curiosity about the rural economy, including its quantitative dimension.