One of the factors that lead to the downfall of the Chaldean empire was the Persian invasion. Although Belshazzar tried to fend off the Persian army, it was too massive to hold off. Another factor would be that Belshazzar was also betrayed by Gobryas, which lead the forces against the Persian army even at greater advantage. Other than the governor, there were also other parties in the state that were also against the Chaldean kingdom. Lastly, there were also the foreign Jew exiles whom Cyrus the Great allowed autonomy and freedom to go back to their homes. From there, it was Cyrus the Great who brought the fall of the Chaldean empire.
