Hadrian also developed permanent fortifications and military posts along the empire's borders ("limites", sl. "limes") to support his policy of stability, peace and preparedness. That helped keep the military usefully occupied in times of peace; his wall across Britania was built by ordinary troops. A series of mostly wooden fortifications, forts, outposts and watchtowers strengthened the Danube and Rhine borders. Troops practised intensive, regular drill routines. Although his coins showed military images almost as often as peaceful ones, Hadrian's policy was peace through strength, even threat, with an emphasis on "disciplina" (discipline), which was the subject of two monetary series. Cassius Dio praised Hadrian's emphasis on "spit and polish" as cause for the generally peaceful character of his reign. Fronto, by contrast, claimed that Hadrian preferred war games to actual war and enjoyed "giving eloquent speeches to the armies" – like the inscribed series of addresses he made while on an inspection tour, during 128, at the new headquarters of Legio III Augusta in Lambaesis