Baghdad Battery

The Baghdad Battery is the name given to a set of three artifacts which were found together: a ceramic pot, a tube of copper, and a rod of iron. It was discovered in present-day Khujut Rabu, Iraq in 1936, close to the metropolis of Ctesiphon, the capital of the Parthian (150 BC – 223 AD) and Sasanian (224–650 AD) empires, and it is believed to date from either of these periods. Similar artifacts have been found at nearby sites. Its origin and purpose remain unclear. It was hypothesized by Wilhelm König, at the time director of the National Museum of Iraq, that the object functioned as a galvanic cell, possibly used for electroplating, or some kind of electrotherapy, but there is no electroplated object known from this period, and the claims are near-universally rejected by archaeologists. An alternative explanation is that it functioned as a storage vessel for sacred scrolls. The artifact disappeared in 2003 during the US-led invasion of Iraq. Physical description and dating The artifacts consist of a terracotta pot approximately tall, with a mouth, containing a cylinder made of a rolled copper sheet, which houses a single iron rod. At the top, the iron rod is isolated from the copper by bitumen, with plugs or stoppers, and both rod and cylinder fit snugly inside the opening of the jar. The copper cylinder is not watertight, so if the jar were filled with a liquid, this would surround the iron rod as well. The artifact had been exposed to the weather and had suffered corrosion.