Five Military Latin Words: Impedimenta, Contubernium, Castra, Auxilia, and Vallum

By Alex Calvo

In recent years, growing numbers have chosen to take A Level Latin. The language remains useful for military historians – even if your period of interest is rather recent; far from the Western World; and no legions feature in it. The following are five military Latin words that you may come across in your reading.

1. Impedimenta (2nd declension, neuter, plural)

Meaning “baggage, baggage train, equipment, supplies…” – the different loads carried by an army on the march. A reminder of the importance of logistics in warfare (an aspect not always studied in the necessary depth, but which we should always take into account when doing research on any campaign).

Note that this is a plural word whose singular form – “impedimentum” – has a different meaning (usually translated as “obstacle, hurdle”) although of course, both are related.

2. Contubernium (2nd declension, neuter, singular)

A group of eight soldiers sharing a tent; the smallest grouping within a Roman army. Members of a contubernium cooked together and shared a mule to transport part of their impedimenta. Some authors have pondered the possibility that this may also be a tactical unit within the larger centuria. In any case, a reminder of the importance of small unit cohesion for morale and fighting spirit.

A contubernium’s mule (or perhaps two such animals) carried its soldiers’ tent (papilio) and hand-mill (mola), in addition to other items and rations.[1]

3. Castra (2nd declension, neuter, plural)

“Camp”, which Roman units on the march would build every evening, affording protection from a night attack. The term also refers to the more permanent fortified bases first built during campaigns far from Rome. These would later give rise to legionary bases once a standing army deployed across the Empire came into being. The concept of permanent legionary fortresses was born in the reign of Emperor Augustus (27 BC AD 14).[2]

The singular form, “castrum” means “castle, citadel”. In Northern England we can find many Roman forts whose name includes “chester” or “chesters” – a derivative of “castra” used by the Saxons to refer to a Roman fortification.[3]

4. Auxilia (2nd declension, neuter, plural)

“Auxiliary troops” made up of non-Roman-citizens, often from the same tribe or region. Although an essential component in Roman armies and of growing importance as the original city state expanded, they differed in many respects; from equipment to command arrangements; from the legions – the backbone of Rome’s armed might. Once again, this is a word whose singular form (“auxilium”) has a different although related meaning – usually translated as “help, aid”.

While legions were above all units of heavy infantry (although also proficient in what we would now call engineering and light artillery), Rome tended to rely to a large extent on auxilia for her cavalry and certain specialised types of weapons such as slings. It was only from the fourth century onward that Roman armies began to rely more and more on their own cavalry.[4] Auxilia also had an important role in policing rural areas, being the first line of defence against revolts.[5]

5. Vallum (2nd declension, neuter, singular)

Vallum at Downhill

Vallum at Downhill

Its general meaning is “trench, defence, rampart, stockade”. In Hadrian’s Wall it refers to “a massive flat-bottomed (and in places rock-cut) ditch flanked by earthen banks, running in long, straight sections to the south of the Wall”, with no known equivalent in the rest of the Empire and whose exact role is unclear. It is believed to have been constructed after the Wall itself and the later added forts, between AD 128 and 133.[6]

Despite doubts on the exact purpose of the Vallum, it seems clear that it was intended to reinforce the ultimate role of Hadrian’s Wall – controlling the movement of civilians. The huge effort involved in its construction confirms that this was no secondary detail. While further archaeological work is necessary to learn in more detail what contribution the Vallum made to the overall Wall system, this is a feature of great interest to the student of counterinsurgency who faces the need to separate insurgents from civilians (it being imperative to control movement and prevent the emergence of sanctuaries).

Roman Wall schematic layout

Roman Wall schematic layout

We should not forget that Hadrian’s Wall was not designed to seal off Roman Britain from the barbarians further north, but to regulate the flow of people and goods. This was in order to provide security – isolating the population from the rebels as Galula would stress[7] -and which was also a goal of coastal defences in Roman Britain.[8] Thus, archaeological surveys have revealed “dozens of Roman-era farms and settlements strung out along a 15-mile corridor either side of the 10ft thick wall. Instead of being wiped out by the Romans, the local population appears to have flourished as part of a booming military economy”.[9]

[1]     Jonathan P. Roth, The Logistics of the Roman Army at War (264 B.C. – A.D. 235), Columbia studies in the classical tradition, Vol. 23, (Leiden; Boston; Köln: Brill, 1998), pp. 77-78

[2]     Duncan B. Campbell, Roman Legionary Fortresses 27 BC – AD 378, (Oxford: Osprey Publishing, 2006), p. 4

[3]     Nick Hodgson, Chesters Roman Fort, (London: English Heritage, 2011), p. 3

[4]     Harry Sidebottom, Ancient Warfare: a Very Short Introduction, (Oxford: Oxford University Press, 2004), p. 89

[5]     Tal Tovy, “’They Make a Solitude and Call it Peace’: Counterinsurgency – The Roman Model ”, Small Wars Journal, 10 December 2012, available at

[6]     Paul Frodsham, Hadrian and His Wall, (Newcastle upon Tyne: Northern Heritage Publishing, 2013), p. 62-64

[7]     David Galula, Pacification in Algeria: 1956-1958, (Santa Monica: RAND Corporation, 1963), p. 23

[8]     Nic Fields, Rome’s Saxon Shore: Coastal Defences of Roman Britain AD 250-500, (Oxford: Osprey Publishing, 2006), p. 18

[9]     Patrick Sawer, “Hadrian’s wall boosted economy for ancient Britons, archaeologists discover”, The Daily Telegraph, 15 November 2008, available at

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