Roman cavalry



Roman cavalry (Latin: equites Romani) refers to the horse mounted forces of the Roman army through the many centuries of its existence.

Early cavalry (to ca. 338 BC)
Romulus supposedly established a cavalry regiment of 300 men called the Celeres ("the Swift Squadron") to act as his personal escort, with each of the three tribes supplying a centuria (century; company of a 100 men), This cavalry regiment was supposedly doubled in size to 600 men by King Tarquinius Priscus (conventional dates 616-578 BC). According to Livy, Servius Tullius also established a further 12 centuriae of cavalry. But this is unlikely, as it would have increased the cavalry to 1,800 horse, implausibly large compared to 8,400 infantry (in peninsular Italy, cavalry typically constituted about 8% of a field army). This is confirmed by the fact that in the early Republic the cavalry fielded remained 600-strong (2 legions with 300 horse each).

An important question is whether the royal cavalry was drawn exclusively from the ranks of the Patricians (patricii), the aristocracy of early Rome, which was purely hereditary. This is certainly the mainstream view among historians, starting with Mommsen. (However, Cornell considers the supporting evidence tenuous.) Since the cavalry was probably a patrician preserve, it follows that it probably played a critical part in the coup against the monarchy. Indeed, Alfoldi suggests that the coup was carried out by the Celeres themselves. However, the patrician monopoly on the cavalry seems to have ended by around 400 BC, when the 12 centuriae of equites additional to the original 6 of regal origin were probably formed. Most likely patrician numbers were no longer sufficient to supply the ever-growing needs of the cavalry. It is widely agreed that the new centuriae were open to non-patricians, on the basis of a property rating.

According to the ancient Greek historian Polybius, whose Histories (written ca. 140s BC) are the earliest substantial extant account of the Republic, Roman cavalry was originally unarmoured, wearing only a tunic and armed with a light spear and ox-hide shield which were of low quality and quickly deteriorated in action.

Recruitment
As their name implies, the equites were liable to cavalry service in the Polybian legion. Equites originally provided a legion's entire cavalry contingent, although from an early stage, when equites numbers had become insufficient, large numbers of young men from the First Class of commoners were regularly volunteering for the service, which was considered more glamorous than the infantry. By the time of the Second Punic War, it is likely that all members of the First Class served in the cavalry, since Livy states that members of Class I were required to equip themselves with a round shield (clipeus), rather than the oblong shield (scutum) required of the other classes - and all images of cavalrymen of this period show round shields. It appears that equites equo privato (i.e. First Class members) were required to pay for their own equipment and horse, but that the latter would be refunded by the state if it was killed in action. Cavalrymen in service were paid 1 drachma per day, triple the infantry rate, and were liable to a maximum of 10 campaigning seasons' military service, compared to 16 for the infantry.

Unit size and structure
Each Polybian legion contained a cavalry contingent of 300 horse, which does not appear to have been officered by an overall commander. The cavalry contingent was divided into 10 turmae (squadrons) of 30 men each. The squadron members would elect as their officers 3 decuriones ("leaders of 10 men"), of whom the first to be chosen would act as the squadron's leader and the other two as his deputies. From the available evidence, the cavalry of a Polybian legion (and presumably confederate cavalry also) was armoured and specialised in the shock charge.

Equipment
Pictorial evidence for the equipment of Republican cavalry is scant and leaves several uncertainties. The earliest extant representations of Roman cavalrymen are found on a few coins dated to the era of the Second Punic War (218-201 BC). In one, the rider wears a variant of a Corinthian helmet and appears to wear greaves on the legs. His body armour is obscured by his small round shield (parma equestris). It was probably a bronze breastplate, as a coin of 197 BC shows a Roman cavalryman in Hellenistic composite cuirass and helmet. But the Roman cavalry may already have adopted chain mail armour (lorica hamata) from the Celts, who are known to have been using it as early as ca. 300 BC. Mail had certainly been adopted by ca. 150 BC, as Polybius states that the First Class were expected to provide themselves with chain mail cuirasses, and the monument erected at Delphi by L. Aemilius Paullus to commemorate his victory at the battle of Pydna (168 BC) depicts Roman cavalrymen in mail. However, a coin of 136 BC and the Lacus Curtius bas-relief of the same period show knights in composite bronze cuirasses.

There is similar uncertainty as to whether cavalryman carried shields (not generally used by Greek cavalry until after ca. 250 BC) and the related question of whether they carried long lances (which normally precluded shields, as they would often be held double-handed) or shorter spears, the doru mentioned by Polybius. Most representations show cavalrymen with the small parma equestris type of shield, but the Ahenobarbus monument of 122 BC and the coin of 136 BC shows cavalrymen without shields. Sidnell suggests that, since equites were expected to provide their own equipment, they may have chosen their own type and combination of armour and weapons e.g. long lance with no shield or short spear with shield. But the evidence is too scant to draw any firm conclusions.

Although there is no pictorial evidence, it is certain from literary accounts that equites carried swords, most likely the same gladii hispanienses (Spanish swords) used by the infantry or the longer spatha. The Ahenobarbus monument also shows a cavalryman with a dagger (pugio). There is no evidence that equites carried bows and arrows and the Romans probably had no mounted archers before they came into contact with Parthian forces after 100 BC.

Campaign record
There is a misconception that Roman Republican cavalry was inferior to other cavalry and that they were just to support their far superior infantry. However, Philip Sidnell, argues that this view is misguided and that the cavalry was a powerful and crucial asset to the Republican army.

Sidnell argues that the record shows that Roman cavalry in Republican times were a strong force in which they bested higher reputed cavalry of the time. Examples include the Heraclea (280 BC), in where the Roman cavalry dismayed the enemy leader Pyrrhus by gaining the advantage in a bitterly contested melee against his Thessalian cavalry, then regarded as the finest in the world, and were only driven back when Pyrrhus deployed his elephants, which panicked the Roman horses. Other examples include the Equites' victory over the vaunted Gallic horse at Telamon and Sentinum, against the Germanic cavalry of the Teutons and Cimbri at Vercellae, and even against the technologically more advanced Seleucid cavalry (including some fully armored cataphracts) at Magnesia.

A key reason for some historians' disparagement of the Roman cavalry were the crushing defeats, at the Trebia and at Cannae, that it suffered at the hands of the Carthaginian general Hannibal during the latter's invasion of Italy (218-6 BC) which were only rendered possible because of a powerful cavalry force. But Sidnell argues that this is only because of a consistent numerical superiority in cavalry. Another disadvantage for the Romans in the Second Punic War was that their respective cavalry were heavily armoured shock cavalry, used to the rudimentary tactic of charging. This, however useful against an infantry that has been routed or is flanked, failed against Hannibal's nimble, Numidian light cavalry that used a skilful, elaborate series of movements that consistently defeated the Roman cavalry. It should be noted that on occasions when they were deployed properly and led competently, such as during the skirmish before Ilipa and at the pitched battles of the Great Plains and Zama, the Italo-Roman cavalry were able to best their Carthaginian counterparts, while at Dertosa they were able to hold their own despite being supposedly outnumbered.

The Second Punic War placed unprecedented strains on Roman manpower, not least on the over 10,000+ drachmae First Class which provided the cavalry. During Hannibal's apocalyptic march through Italy (218-6 BC), thousands of Roman cavalrymen were killed on the battlefield. The losses were especially serious for the knights properly so-called (equo publico): Livy relates how, after Cannae, the gold rings of dead Roman knights formed a pile one modius (ca. 9 litres) large. In the succeeding years 214-203 BC, the Romans kept at least 21 legions in the field at all times, in Italy and overseas (and 25 legions in the peak year). This would have required the knights to provide 220 senior officers (120 tribuni militum, 60 decuriones and 60 praefecti sociorum). It was probably from this time that the 18 centuriae of knights became largely an officer class, while the 6,300 Roman cavalrymen required were raised from the rest of the First Class.

The cavalry of Roman armies before the Second Punic War had been exclusively Roman and confederate Italian, with each holding one wing of the battleline (the Romans usually holding the right wing). After that war, Roman/Italian cavalry was always complemented by allied native cavalry (especially Numidia), and was usually combined on just one wing. Indeed, the allied cavalry often outnumbered the combined Roman/Italian force e.g. at Zama, where the 4,000 Numidians held the right, with just 1,500 Romans/Italians on the left. One reason was the lessons learnt in the war, namely the need to complement heavy cavalry with plenty of light, faster horse, as well as increasing the cavalry share when engaging with enemies with more powerful mounted forces. It was also inevitable that, as the Roman Republic acquired an overseas empire and the Roman army now campaigned entirely outside Italy, the best of non-Italian cavalry would be enlisted in increasing numbers, including (in addition to Numidians) Gallic, Spanish and Thracian horse. Towards the end of the republic and the beginning of the Roman Empire, the Roman cavalry itself was rendered less and less of a powerful force, with Rome meeting its cavalry needs with auxiliary, allied cavalry instead.

Nevertheless, Roman and Italian confederate cavalry continued to form an essential part of a Roman army's line-up for over a century. They were again, less successful against elusive tribal cavalry such as the Lusitanians under Viriathus in their bitter resistance to Roman rule (151-140 BC) and the Numidians themselves under king Jugurtha during the latter's rebellion (112-105 BC), when they were obliged to rely heavily on their own Numidian allied horse and the Romans were deprived of their strongest cavalry.

End of the citizen cavalry
The Jugurthine War is the last war in which Roman/Italian confederate cavalry is attested as having played a significant part. After that references to the citizen cavalry become rare and the Roman army seems to have become largely dependent on non-citizen cavalry, either recruited in the subject provinces or supplied by allied kings. As part of the army reforms of Gaius Marius around 107 BC, citizen legionary cavalry was abolished and entirely replaced by native allied cavalry. This process may have happened gradually as a result of the grant of Roman citizenship to all of Rome's Italian confederates after the Social War (91-88 BC), which led to the abolition of the old Italian confederate alae and the recruitment of all Italians into the legions. For the cavalry, the abolition of the alae had the radical result of reducing the Roman/Italian cavalry to just a quarter of its previous size, since legions contained only a third as many horse as confederate alae. Legionary cavalry was thus reduced to a fraction of a Roman army's overall cavalry complement: a consular army of 2 legions now contained about 20% cavalry (i.e. ca. 4,000 horse), of which, at most, only 600 were Romans. Indeed, the Roman element may now have numbered just 240, as it is possible that around this time, the legionary cavalry contingent was reduced to 120. It also appears that from this time onwards, Roman knights were no longer levied for cavalry service, which was now recruited from Italian commoners. By the time of Gaius Julius Caesar's Gallic War (58-51 BC), it appears that legionary cavalry may have disappeared altogether, and that Caesar was entirely dependent on allied Gallic contingents for his cavalry operations. This is deduced from an incident in 58 BC when Caesar was invited to a parley with the German king Ariovistus and needed a cavalry escort. Since he didn't yet trust the allied Gallic cavalry under his command, he instructed them to lend their horses to some members of the Tenth Legion, which thereafter acquired the nickname equestris ("mounted legion"). (However, this incident leaves open the possibility that Roman cavalry still existed, but was not large enough to satisfy the needs of the moment).

The question arises as to why the Romans allowed their citizen cavalry to lapse in this way, given its record as a highly effective and useful force. The main reason is probably the limited pool of available equites and First Class members. The equites had long since become exclusively an officer class (a role they retained throughout the Principate), as the empire had become simply too large and complex for aristocrats to serve as ordinary troopers. At the same time, many of the First Class of commoners had developed major business interests and had little time for military service. Although Italian commoners of the lower classes could, of course, have been recruited and trained as cavalrymen in larger numbers, that must have seemed costly and unnecessary when subject countries such as Gaul, Spain, Thrace and Numidia contained large numbers of excellent native cavalry which could be employed at much lower pay than citizens.