Defence in depth in order to retreat successfully, and they assume that the defender's morale will recover from the retreat. A possible early example of this came at the Battle of Cannae in 216 BC, when Hannibal employed this manoeuvre in order to encircle and destroy eight Roman legions, but that is disputed by some historians. Edward Luttwak used the term to describe his theory of the defensive strategy employed by the Late Roman army in the 3rd and 4th centuries AD. Later examples of defence in depth might be European hill forts and the development of concentric castles. In those examples, the
History of Sardinia et Sardinia, under a praetor. Together with Sicily it formed one of the main granaries of Rome until the Romans conquered Egypt in the 1st century BC. A revolt, led by two Sardo-Punic notables from Cornus and Tharros, Hampsicora and Hanno, broke out after the crushing Roman defeat at Cannae (216 BC). A Roman army of 22.000 infantrymen and 1.200 knights, under Titus Manlius Torquatus, reached Sardinia landing in Caralis and defeating Hiostus, the son of Hampsicora, near Milis. The Romans then met the Carthaginian-Sardinian allied forces in the south of the island, defeating them in a pitched battle that