One of the most interesting arguments for ancient technology comes from the discovery of the Bagdad batteries. These small pots which were found in the proximity of today's Baghdad are the best candidates for electro-chemical devices found so far.
Some of the pots were also found in the Parthi settlements, which was inhabited around the time of Christ's birth. Other pots even might have to be settled into the period to 1200 CE. What these pots were used for is still being figured out. One thing is for sure they were capable of producing an electric current - and most likely did. All of this way before Edison.
