The exact date that the fortress was constructed is unknown, but it is known that the mountain pass belonged to the nobility in the 10th century, and that Bagrat III, the first king of united feudal Georgia, engaged in a significant battle in order to capture it. After that the fortress came into the possession of the Georgian kings.
The unconquerable fortress has seen many battles. We know that Tahmasp I, Shah of Iran, who invaded Georgia in 1556, was forced to cut off the supply of water in order to take the fortress - a process that took multiple bloody attacks.
Historical sources tell us that the fortress once had strong, high walls, a fence, and was bolstered with bulwarks. There were quarters for defenders, a hidden water reservoir, and other buildings necessary for enduring a lengthy siege. Even now you can see fragments of these remaining.
The impregnable Ateni Fortress fell into ruin at the beginning of the 17th century, when Rostom, the king of Kartli, went to war with the rebels supporting King Teimuraz. The fortress was dealt a final blow during the 1920 earthquake, with only its ruins standing today.