24

HIERARCHY AND COMMAND-STRUCTURE IN THE ROMAN ARMY1

The military hierarchy and the military command-structure represent two different aspects of army organization. While the former expresses a set of social relations in the barracks, the latter determines the way an army functions as an organized fighting force. For the individual, the positions he occupied in the hierarchy d~ring the course of his career reflect his social status as a Roman soldier and afterwards in civilian life. Thus these are listed on many public and private inscrip• tions and have provided the material for extensive research by modem scholars, ever since van Domaszewski published his major study, Die Rangordnung des ro'mischen Heeres. The combined study of literary sources and inscriptions has done much to clarify the relationships between ranks in all parts of the , although there are problems which remain to be solved and others which may never be solved on the available evidence. Elucidation of the hierarchy, however, does not necessarily help in understanding the command-structure, or chain of command, although obviously there must always be some connection between rank and function in a large organization. While our sources abound in refer• ences to specific ranks in the army, they provide far less information about what the people holding these ranks were actually doing, in war or in peace-time. Systematic study has therefore focused more on the hierarchy than on functions or command-structure. It is the aim of this paper to show that there are various unresolved problems with regard to the chain of command in the Roman Imperial Army, from the first till the fourth centuries, which need to be addressed if we want to understand the basic principles of its organization. Every army, ancient or modem, needs a chain of command to con• vey the orders of its general to the individual soldiers. The command structure depends on the system which groups soldiers into the units

1 School of History, Tel Aviv University, Ramat Aviv 69978, Israel. HIERARCHY IN TifE ROMAN ARMY 389 which, when combined, make up the fighting force. We should like to deal here with the specific question of which officer filled the gap between the legionary legate, who commanded almost 6000 men, and the legionary , who commanded 80. The principle of a chain of command is clearly defined in some of our sources and can occasionally be seen as functioning in practice. Onasander, in the middle of the first century A.D., observes that the general should transmit his orders through officers. 2 Julius Caesar frequently describes himself as giving orders through his legati and tribuni, or addressing his .3 Very few sources, however, give specific information about the command-structure in peace-time, or the order of battle when the army acted as a fighting force. This distinction has to be made, for on the battle-field the army operates on a massive scale, while in peace-time its constituent units maintain themselves inde• pendently and often operate on a small scale. First, however, brief mention should be made of the organization of the republican legion. It seems that, originally, the legion was an administrative unit, not a tactical one. 4 As described by Polybius (vi 24) the legion was divided into thirty maniples,5 each commanded by two centurions,6 assisted by two optiones (ou' oupayouc;) and two standard-bearers (CTTJµatoq,6pouc;). There is no suggestion in Polybius that the maniple was subdivided into tactical units of centuries, com• manded by their own officers: the two centurions are said to com• mand 'a half maniple'. 7 The term '' or its equivalent does not exist. There is no reference to any other unit above the level of the maniple and the is nowhere mentioned. Each legion had six tribunes, but these had no specific function in the chain of com• mand, but were experienced officers in this period (vi 19-20; 27, 4). Polybius' description of the Roman army camp suggests that there

2 Onasander, strategi,cus, 25. 3 Caesar, BG iv 23; vii 52; also: v 37; vi 7. 4 8, 8-10; 14. 5 Polybius gives four synonyms for the term maniple (vi 24, 5): 1cat to µEV µepo~ EKaatov EKaAEaav Kat tayµa Kat mtt'ipav Kat cniµaiav .... It follows that the term· a1tt1pa is used here for a maniple rather than a cohort, as in the Early Empire, or as in Polybius xi 23 (below, n. 20). 6 The officers of the maniple are called 'centurions' or 'taxiarchoi': tou~ o' iwtµov~ (EKIXA.Eaav) KEVtupfrova~ Kat ta~tlXPXOU~. 7 The maniple has two officers, says Polybius, because it should never be without a commander. If there are two centurions each commands one half of the maniple, but if there is one, he commands the entire maniple.