The project deals with the original constitution and subsequent transformations of an archaeological site dating from the Ilkhanid (Mongol) period (thirteenth to fourteenth century): the Rabʿ-i Rashīdī of Tabrīz. It was founded as a pious endowment (waqf) by the statesman Rashīd al-Dīn, who embedded his mausoleum into an ensemble of religious, educative and charitable institutions. Extant structures on the site are mainly of later origin (sixteenth to seventeenth century), but excavations have yielded material datable to the founding phase. The article gives an overview of the site and the respective written sources, introduces results of the first phases of fieldwork and an analysis of materials on hydraulic installations. While by the express will of the founder and by its juridical nature the original endowment was conceived as a perpetual institution, the archaeological remnants suggest substantial transformations in later periods. It seems that the site persisted thanks to its natural resources, which were exploited for civil and military purposes.