This is not intended as an introduction to the centurionate or legionary organisation in general, but rather as a convenient aide-memoire to sort out who was doing what to whom and with what when it came to building Hadrian’s Wall. Nevertheless, a little background detail needs to be sketched in, hopefully with the lightest of touches.
Everybody knows a legionary centurion (centurio) commanded a century (centuria) of 80 men, don’t they? That is certainly their basic function, but we also find them commanding entire auxiliary units or even detachments of units (vexillationes). Centurions were very versatile and they included within their ranks a wide range of experience.
The Late Roman epitomist, Flavius Vegetius Renatus (known to all who love and loathe him as just Vegetius), author (perhaps ‘compiler’ is better¹) of the De Re Militari (also known as the Epitoma Rei Militaris), had something to say about legionary structure. He tells (DRM 2.6) how a legion lined up its cohorts in two rows on the battlefield, with cohors I on the front at the right (the position of greatest honour) and so on to cohors X in the second row on the left (you get the picture, I’m sure, but just in case, I’ve drawn you a diagram; just in case you think ‘but cohors I is on the left!’, think of it from the Roman point of view).
He also said that the better recruits went to the right, centre, and left cohorts of both lines (I, III, V, VI, VIII, and X) because of their important positions on the battlefield and I’ve picked those out with a darker shade. All of this, he asserted, was reflected in the rank structure of the centurions, so that the senior centurion of cohors I was at the top – and the junior centurion of cohors X at the bottom – of the pile. Much academic ink has been spilled debating the merits and demerits of this supposed hierarchy and no firm conclusion reached. Suffice it to say: there was a structure of sorts.
We know that each of cohortes II–X had six centurions: pilus prior, pilus posterior, princeps prior, princeps posterior, hastatus prior, and hastatus posterior in descending order. Here’s another diagram (orientated as above, with the enemy at the bottom):
Nice, eh? But before you become too confident, you should know that cohors I was rather different; there, the primus pilus was the senior centurion (with a double-strength century) and he was accompanied by the princeps (primus), hastatus (primus), princeps posterior, and hastatus posterior. Collectively, they were the primi ordines. These look like this:
One last detail is rather intriguing. The Roman army sometimes used a special grammar of symbols to represent the different types of centurions. These symbols, which are known from inscriptions from the legionary bases at both Mainz (Germany) and Lambaesis (Algeria), graphically represent the position of the century within the cohort. Like so (same orientation):
No examples have been found in Britain yet but that is no guarantee that they were not used here too.
As the army were building the Wall, they recorded the sections undertaken by the various centuries with inscribed indicating the names of the centurions. It is generally supposed that only detachments from the three British legions (II Augusta, XX Valeria Victrix, and the newly arrived VI Victrix) took part in the construction process, a proportion remaining back at the respective bases of the legions (Caerleon, Chester, and York). Some centurial stones specifically mention the cohort:
whilst others imply it (> P P was the abbreviation for centuria primi pili and the only primus pilus in a legion was in cohors I). Some stones record distances constructed and 30ft occurs on three stones from Wall Mile 49 (1917, 3416, 3426). As is pointed out by the editors of RIB III, centurions carried a ten-foot measuring pole, the decempeda, so 30ft is an obvious natural multiple of that convenient standard.
Centurial stones are rather informal affairs (seldom mentioning the actual legion involved), and completely different to the massive distance slabs on the later Antonine Wall.
Out of all of this, many years ago, C. E. Stevens drew up a list² of legionary centurions and their cohorts mentioned amongst the Wall inscriptions (including those that can be deduced from centurial stones mentioning the primus pilus, who was, of course, always in cohors I). With a little bit of imagination (and no small amount of jiggery pokery), we can tentatively break this down by legion (and this mostly follows Stevens’ Appendix IV):
Legio II Augusta
Primarily recorded in the stretch either side of Housesteads.
Cohors I: ? primus pilus (1373), Claudius Augustanus (1770, 3297), Terentius Cantaber (1568)
Cohors II: No centurions recorded
Cohors III: Claudius Augustanus (1811, 1855), [Volusiana] (1441)
Cohors IV: Pedius Quintus (1400), [Probiana] (1868, 1930)
Cohors V: No centurions recorded
Cohors VI: Aprilis (1401), ?Iulius Tertullianus (1970, 2016)
Cohors VII: Pompeius (1649),
Cohors VIII: Caecilius Clemens (1440, 2081), Florianus (1575), Iulius Primus (1369), ?Iulius Tertullianus (1970, 2016)
Cohors IX: No centurions recorded
Cohors X: No centurions recorded
Legio VI Victrix
Primarily recorded in the stretch west of the River Irthing.
Cohors I: primus pilus (3427)
Cohors III: Sollius Iulianus (3454); cf 3437 (no centurion named)
Cohors VI: Cassius Priscus (1415, 1869, 3456), Eppius Constans (3430, 3451), Faenius Alexander (3433), Pompeius Albinus (3449)
Cohors VII: ? (2076), Atilius Natalis (3422)
Cohors VIII: Flavius Bassus (3424), ?Florianus (1937), Hellenius (3296), Iulius Primus (3425)
Cohors IX: ?Florianus (1937), Marcius Rufus (1943, 3417-8)
Cohors X: No centurions recorded
Legio XX Valeria Victrix
Primarily recorded in the stretch east of the River Irthing and between Chesters and Carrawburgh.
Cohors I: ? primus pilus (1502, 1503), Flavius Civilis (1474?), Flavius Crescens (1763), Olc(…) Libo (1647, 1849, 1857, 3382), Nas(…) Bassus hastatus posterior (1473, 1501, 3306), Pompeius Rufus princeps primus (3308), Serenus primus pilus (3408), Valerius Sabinus (3412)
Cohors II: Ob(…) Libo (3411), Laetianus (1851, 3391)
Cohors III: Claudius Augustanus (1855), Ferronius Vegetus (1769), Maximus Terentius (3386, 3387), O…, Senilis (1755), Socellius (3413)/[Socelliana] (1675, 1768)
Cohors IV: Liburnius Fronto (2077), Terentius Magnus (2077)
Cohors V: Caecilius Proculus (1475-6, 1570), Gellius Philippus (3407), Iulius Valens (1774, 3409), Sextius Proculus (1754), Valerius Maximus (1766), Valerius Rufinus (3377)
Cohors VI: Caledonius Secundus (1679, 1854, 3379, 3385), [Decimiana] (1505), Gellius Philippus (1572, 1668, 3303), [Lepidiana] (1772), Liberalis (1508, 1678), Lousius Suavis (1499, 1506, 1681, 1859, 1861, 3401)
Cohors VII: No centurions recorded
Cohors VIII: [Sabiniana] (1497), Seccius (1757, 1764), Valerius Verus (1761, 1853, 2083, 3390)
Cohors IX: Aelius Aelianus (1498), Flavius Noricus (1664), Paulius Aper (1444)
Cohors X: Flavius Noricus (1762, 1812, 3378), Iulius Commidus (1514), Iulius Florentinus (1762), Iunius Rufus (1509), Matellius Ursus (1500), Munatius Maximus (3323), Vesuius Rufus (1858, 2084)
Many centurial inscriptions – probably most – do not cite a parent cohort, so can only really offer confirmation for those that do and are excluded here. Centuries lacking their centurions are indicated within square braces ; RIB numbers are in brackets ().
Stephens’ study of the centurial inscriptions was an elegant piece of epigraphic detective work that enabled him to work out that the Second and Twentieth legions built the curtain wall between Wallsend and the Irthing (with the Sixth building most of the forts), and the Second and Sixth between the Irthing and Bowness. The implication of his conclusions seems to be that the Sixth were either not there for the fun and games to begin, but arrived in time for the ‘forts decision’, or that they built the Turf Wall to the west whilst the other two were preoccupied with the eastern stone section. The Sixth may even have had a little help from their friends, the Classis Britannica (1340), who had brought them across the Ocean (1320) with the help of Neptune (1319), and went on to build Benwell fort (1340). However, it should be pointed out that Breeze and Dobson differed in their opinion of which legions did what.
Our knowledge of the various centurions is clearly largely dependent upon the excavation and consolidation of the Wall undertaken so far and it currently favours the Twentieth over the Second Legion, but that may change over time. The list above shows centurions from every cohort of the Twentieth Legion except Cohort VII, which may imply that it was left back at the legion’s base at Chester. Other cohorts (III, V) had up to five centurions present, whilst Cohort VI had all six centuries, although two of them were without centurions (so presumably commanded by the deputy or optio). The First Cohort has seven named centurions recorded, so presumably there had been some transfer and/or promotion whilst the unit was working on the Wall. Some centurions resolutely refused to provide a cohort number and these presumably filled in some of the gaps.
And so, dear reader, you now know something of the body of centurions of the Exercitus Britannicus, cajoling (and probably, on occasion, cudgelling) their charges into constructing a more-or-less adequate stone wall. You can see all of them named here:
Stevens commented in the conclusion to the second edition of his work:
If the complications of my picture in 1947 ‘amazed’ a reader, I know not what verb would be appropriate for this Second Edition.
¹ Vegetius is all too reminiscent of a school child using Wikipedia to do his homework, although he has a range of sources at his disposal, of varying quality, but he has nevertheless disengaged his critical faculties. He seems to quote whole chunks verbatim and then has a habit of inserting a banal comment of his own, as if to show he has actually been paying attention.
² Stevens, C. E. (1966) The Building of Hadrian’s Wall, CWAAS extra series 20, Kendal