Definition of Mediastinum. Mediastinum: The area between the lungs. The organs in the mediastinum include the heart and its large veins and arteries, the trachea, the esophagus, the bronchi, and lymph nodes. Search MedTerms:
The Pax Romana ended because the Roman state had ceased to grow. Boundaries had been set for the Empire, and for the first time the army had become a drain on the econom â¦ y of Rome. Till this point the army provided new slaves and riches from conqured countries.
Edward Gibbon, author of The History of the Decline and Fall of the Roman Empire is sometimes credited with the idea of the Pax Romana. 1  He writes: 2  Then, when the soldiers retired, they generally settled in the land where they had been stationed.