The Encyclopaedia for the Antiquity and Christianity (RAC) is a fundamental instrument for researching Late Antiquity. In interdisciplinary investigations, the “examination of Christianity with Antiquity” is investigated, which means the multifaceted examination process of Christian, Jewish, as well as pagan Antiquity and the accompanying transformations into late antique culture up to the 7th century. Not only phenomena of the religious life, theological notions and beliefs come up for discussion but also state and society, law and economy, literature, art and science, daily life, and material culture.
The Greek- and Latin-speaking regions of Europe and the Mediterranean world are considered as well as regions where different languages are articulated, in which the examination process can be proven, especially the Judaism in Palestine and the diaspora. The issues in question, Christian and not Christian, are presented regardless of the editor's confessional or ideological point of view.
The research program “Antiquity and Christianity” trace back to Franz Joseph Dölger (†1940), a historian of religion and church. The Bonn church historian Theodor Klauser (†1984) created the Encyclopaedia for the Antiquity and Christianity with him, Hans Lietzmann (†1942) and further colleagues.