Heortology or eortology is a science that deals with the origin and development of religious festivals,[1] and more specifically the study of the history and criticism of liturgical calendars and martyrologies.
[6] In parallel with modern archaeology, studies also examined the question of the rites of Greek and Roman antiquity, following the work of August Mommsen, published in Leipzig in 1864 under the title of Heortologie: Antiquarische Untersuchungen über die städtischen Feste der Athener.
German scholar Karl Adam Heinrich Kellner published Heortologie, oder, das Kirchenjahr und die Heiligenfeste in ihrer geschichtlichen Entwicklung in Freiburg im Breisgau in 1901.
At the same time, Mircea Eliade focused on the importance of religious thought on contemporary society through his heortological studies of primitive religions.
Thus, ancient civilizations commemorate as the victory of a hero over a serpent-god, or the betrothal of the Earth to the Sun while for Christians, Easter is the solemn celebration of the resurrection of Jesus Christ.