 Di Peso first worked for the Amerind Foundation in 1948 and in 1954 became the director which he held until his death in 1982.Di Peso is best known for his excavation, analysis, and interpretation of archaeological materials from Paquimé, also known as Casas Grandes, beginning in 1959.According to Di Peso, Paquimé was established by Mesoamerican merchants in order to control trade between Mesoamerica and the Southwest.