Kircher cited as his sources Chaldean astrology, Hebrew kabbalah, Greek mythology, Pythagorean mathematics, Arabian alchemy and Latin philology.

The primary source for Kircher's study of hieroglyphs was the Bembine Tablet, so named after its acquisition by Cardinal Bembo, shortly after the sack of Rome in 1527.

His renditions of hieroglyphic texts tended to be wordy and portentous; for example, he translated a frequently occurring phrase in Egyptian, dd Wsr, "Osiris says," as "The treachery of Typhon ends at the throne of Isis, the moisture of nature is guarded by the vigilance of Anubis."

According to E. A. Wallis Budge: Many writers pretended to have found the key to the hieroglyphics, and many more professed, with a shameless impudence which is hard to understand in these days, to translate the contents of the texts into a modern tongue.

Foremost among such pretenders must be mentioned Athanasius Kircher, who, in the 17th century, declared that he had found the key to the hieroglyphic inscriptions; the translations which he prints in his Oedipus Aegyptiacus are utter nonsense, but as they were put forth in a learned tongue many people at the time believed they were correct.