In 1938, the German archaeologist Wilhelm Konig reportedly excavated the five-inch (13-cm)-long clay jar in Khujut Rabu, near Baghdad, Iraq (though some reports say it was found in the collections of the National Museum of Iraq). The jar contained a copper cylinder, in turn covering and protecting an iron rod, isolated from the copper by asphalt. The artifact had been exposed to the weather and had suffered corrosion.

Konig published paper reporting the mechanism's resemblance to a battery in 1940. Upon publication, Konig's discovery was discounted by the scientific community and soon disregarded. Such ancient knowledge in the history of electricity bears no known continous relationship to the development of modern batteries. Its form, though, is nearly identical to the principles that are in use today. After the Second World War, Willard Gray demonstrated current production by a reconstruction of the inferred battery design when filled with substances, like grape juice. Subsequent tests found acidic residues in the original, analysed as an electrolytic solution, perhaps vinegar or wine.

Some people regard the Baghdad Battery as an anachronism (appearing to be out of place in time), this is from the idea that ancient civilizations did not have electrical power and they therefore wouldn't have any device which operated on the principles of electric power. The practical uses of this battery is uncertain. Some contemporary researchers have renewed interest in interpreting this artifact, and suggested electroplating precious metals as a practical use for early batteries by Baghdad Parthians (who used it to electroplate metallic items; e.g. put a thin layer of gold over an object made out of some other metal). Artifacts from ancient Egyptian sites, similarly resembling batteries, or bearing traces consistent with precious-metal electroplating, may support that.

See also

• Anachronism
  • Electricity
  • Ark of the Covenant
• Pseudoarchaeology
  • Anachronism and time travel