Answer:
Short term:
On the death of Augustus, in AD 14, three legions stationed in Pannonia (present-day Hungary) rebelled. In his Annals of him, Tacitus explains that the mutiny began when the commander loosened discipline and the troops indulged in idleness and slander. In the image, a funeral stele of a Norse rider of a legion. 1st century Museum of Roman Civilization, Rome.
Long term:
Since its transformation into a professional army, composed of disciplined and efficient men, the legions of Rome were the spearhead of the Empire. In the image, brooch with insignia of the X Legion. 1st century Israel Museum, Jerusalem. A legion was an efficient war machine, but also a disciplined group of workers capable of building roads, bridges, aqueducts, levees, ports, and forts. The latter could be permanent or temporary, built according to the same scheme but with different materials. In this illustration by Peter Conolly, a legionnaire cleans and repairs his armor from him in front of his barracks.
