Egyptology is the study of ancient Egypt through its written record, hieroglyphic, hieratic and later demotic script, and its excavated material culture, temples, tombs, papyri and inscribed objects. The discipline began in 1822, when Jean François Champollion announced to the Académie des Inscriptions et Belles Lettres in Paris that he had deciphered Egyptian hieroglyphic writing, working from the trilingual Rosetta Stone and a set of royal cartouches whose repeated names let him work out which signs represented sounds. Champollion's decipherment turned a monumental but mute civilization into one whose own religious and administrative texts could finally be read directly rather than filtered through Greek and Roman description.
Before 1822 everything the wider world knew about Egyptian religion, its gods, temple ritual and funerary belief, came from Herodotus, Plutarch and other outside observers writing centuries after the fact. Egyptology replaced that secondhand account with the religion's own texts, coffin inscriptions, temple hymns and the Book of the Dead among them, in the god's own language. The atlas relies on Egyptological translation and dating wherever it describes Egyptian deities, temple practice or funerary belief, rather than on the classical authors who wrote about Egypt from outside it.