The beginning of the development of the archival holdings of the Polish Province of the Order of Piarists dates back to the period between the wars, although their current state generally reflects the long-term efforts of archivists following World War II. The holdings include archival items created in the period from the seventeenth century to the present. Among the most valuable archive materials is, unarguably, Matricula Provinciae Poloniae Scholarum Piarum, covering the period 1742-1867. It is the source most often used for academic research. It is worth emphasising, however, that in the archival holdings we can also find many other valuable archival materials such as chronicle-like books, files of the Chapter, school books, and inventories.