Classics is the study of ancient Greek and Roman language, literature and culture, asking what a classical text actually says in its original language and how confidently a claim about Greek or Roman religion can be traced back to a primary source rather than a later paraphrase. The German scholar Friedrich August Wolf became, in 1777, the first person admitted to the University of Gottingen as a student of philology in its own right rather than as a branch of theology, and went on as professor at Halle to argue for philology as an independent discipline combining language, history and textual criticism into one method for recovering antiquity on its own terms.
Wolf's insistence on philology as a discipline in itself, rather than a subordinate tool of theology, is what makes classics able to test a claim about ancient Greek or Roman religious practice against the actual surviving text rather than against how a later tradition has chosen to summarize it. The atlas relies on classical philology wherever a claim about Greco-Roman religion, an oracle's wording, a hymn's authorship, a myth's earliest attested version, needs to be checked against the primary Greek or Latin source itself.