Rome

Rome was a powerful civilization and it was though towards the end when it ran out of countries to subjugate and slaves to capture which brought down the economy. As soldiers weren't getting paid and slaves couldn't be brought in and bought so that brought down the economy down. Then mutinies and rebellions happened made the country war-torn then invading tribes attacked and eventually brought Rome all the way down and Rome became nonexistent. Well not totally only the western half failed and fell. The eastern half was renamed byzantine and lasted a while longer though it was not a very militarily built country and was weak but traded with everyone.