Livy's books 21-44 contain roughly ninety battles, about half of which are mentioned only briefly, though usually including figures on casualties, captives and booty. Livy's full-scale narratives show differences in style, nature and content, including technical matters like the terminology used for units of the Roman army. Comparison between Livy's and Polybius' narratives on the battles of Cynoscephalae, the Great Plain and Zama show that Livy closely adhered to the terminology of his sources. Differences in terminology therefore reflect Livy's use of different sources. One set of Livian battle scenes is characterised by the numbering of legions and by details concerning allied units. Various elements indicate a late-annalistic origin for these battle narratives, identified here as Valerius Antias. Battle narratives of this type are limited to particular periods and regions: Italy during the Second Punic War; Spain and Gaul from the end of the Second Punic War onwards. This shows that Livy decided on this particular source for these particular theatres of war. Outside these parts of his account, Livy briefly summarised the battle narratives he found in his predecessor's work.