The High Water Mark
Contributed by David Verne
This spring Trajan and part of the army sailed down the Tigris to the Persian Gulf where they captured the important trade city of Charaxes. As he looked out over the ocean, Trajan expressed regret that he was too old to continue to India like Alexander the Great. Trajan also took the time to visit the ancient city of Babylon. While Trajan was playing tourist and taking in the sights, the conquered territories revolted and expelled the garrisoned Romans. Trajan managed to reconquer most of the Parthian territory, but instead of annexing it, he appoints a Parthian nobleman to rule Parthia as a client kingdom. While the Romans were successful, this year wore them down, and the elderly emperor was exhausted so they returned to Antioch. 
- Dando-Collins, Stephen (2010). Legions of Rome. St. Martin's Press.