George Rawlinson,
The Seven Great Monarchies Of The Ancient Eastern World…
“ The clouds of Parthian horse hung upon their retreating columns, straitened them for provisions, galled them with missiles, and destroyed those who could not keep up with the main body. The towns upon the line of their retreat revolted and shut their gates, defying even such commanders as Severus and Trajan. Of the six great expeditions of Rome against Parthia, one only, that of Avidius Cassius, was entirely successful. In every other case either the failure of the expedition was complete, or the glory of the advance was tarnished by disaster and suffering during the retreat. ”
