Acta Sanctorum (Acts of the Saints) is an encyclopedic text in 68 folio volumes of documents examining the lives of Christian saints, in essence a critical hagiography, which is organised according to each saint's feast day. It begins with two January volumes, published in 1643, and ended with the Propylaeum to December published in 1940. The Acta Sanctorum have from the start been at the forefront of the critical method of scholarship.
The Societé des Bollandistes, named for the Jesuit scholar Jean Bolland ('Bollandus', 1596–1665), has overseen this mammoth undertaking, first in Antwerp and then in Brussels. When the Jesuits were suppressed by the Habsburg governor of the Low Countries in 1788, the 'Bollandistes' continued their work, in the Abbey of Tongerloo. From 1643 to 1794, 53 folio volumes of Acta Sanctorum had been published, covering the saints from January 1 to October 14.
The many 'Lives of the saints' are essential sources in our knowledge of societies, cultures and civilizations of the Christian world, even secular aspects not directly related to cult or doctrine. A saint is a person of note. The saint exercises an influence on society in civil as well as ecclesiastical affairs. After the saint's death, the communities which the saint has created, institutions he or she has founded, rules drawn up, and even the nature of the cult rendered to the saint, are the raw material of history. As the Societé states in defending the usefulness of hagiography in wider contexts,
- "It is also the case that much of what we know as history from the beginnings of Christianity to the Middle Ages is known only thanks to hagiographical texts. Even in the modern period it is impossible to speak of history, archaeology, architecture, sculpture, painting, music, literature, folklore, or ethnology, without calling to mind the life and cult of some saint. Even in the study of law, are not some of the most ancient documents found in the Acts of the martyrs? Almost all the fairs of the Middle Ages, international, national, and regional, were attached to the memory of a saint. Every detail of domestic and public life is found in the Acts of the saints. And they show us as much about the lives of every-day folk as about prominent people.
- "This is why the Acta Sanctorum embrace general history (civil as well as ecclesiastical); the particular history of different countries, towns, and monasteries; the chronology, geography, and topography of a large part of the globe: and all of this from the beginning of the Christian era up to the 16th century.'