When the ruling class of Rome would become too corrupt or unjust to the commoners, the commoners banded together, evacuated the entire city and left the elites to fend for themselves. 
Discussion
The Secession of the Plebians!
The Plebians came back when they were promised equality before the law and an unchangeable set of laws cast in bronze, the Twelve Tables.
Unfortunately, the base layer was designed to run on lawyers, not cryptography, so it was quickly corrupted.