The work of Tacitus most single-mindedly focused on war (at least in its surviving portion) is unquestionably the Histories. From the point when Vitellius begins his invasion of Italy (1.51) war stands consistently at the centre of the narrative, as the war between Vitellius and Otho gives way to one between Vitellius and Vespasian, which is almost immediately succeeded by the narrative of the revolt of Civilis, punctuated in Book 5 by the beginning of the Jewish War. Although this may be part of what has made the Histories considerably less popular than the Annals among modern readers - military history appealing to a narrower audience than political and dynastic intrigue - it is entirely expected of a historical narrative in the ancient world. Indeed it was commonplace for an entire history to focus on (as it might be) 'the Peloponnesian War' or 'the Jugurthine War'; and even when (as with Livy) the history purported to cover all the events, domestic as well as foreign, of a state over a longer period, war was often used for the purposes of structural articulation within the narrative (so Livy groups many of his books in 'pentads' and 'decades' according to the wars that were taking place in them).