The bulwark of Seleukid power was the military, particularly the royal army. The support of the army enabled Seleukos I to establish himself first as satrap of Babylon and later as king – none of his successors were able to maintain their position without the army’s support. As a body, the army provides a second insight into the ethnic composition of the population living under the kings. Unfortunately the extant historical sources, deficient at the best of times in regards to the Seleukids, provide the modern scholar with only three detailed breakdowns (listing nationalities and numbers) of the Seleukid order of battle. Of these, two represent the army in pitched battle (Raphia, 217 BC and Magnesia, 190 BC), the other is a description of a festive military parade (Daphne, 167 BC). That said, the three examples taken together can be used to extract a great deal of information regarding the sources of manpower in the royal army during the late third and early second centuries BC.
In 217 BC, the Fourth Syrian War was decided outside Raphia on the border of Koile-Syria and Egypt. Antiochos III the Great commanded a large field army that had thus far been successful in driving the Ptolemies out of Koile-Syria. Polybius provides a detailed description of the troops present and their respective roles in the battle in which Antiochos commanded the right flank in person and forced his opponents to flee the field. With their commander distracted, the Seleukid left flank was defeated and the centre outflanked and routed. Antiochos was forced to abandon his conquests and the region remained Ptolemaic for another 17 years until the Koile-Syrian question was settled in favour of Antiochos at the battle of Panion. The Seleukid infantry at Raphia were broken down into the following contingents: 20,000 phalangites and 10,000 elite agyraspidai all equipped in ‘Macedonian’ fashion; 5,000 Greek mercenaries; 1,500 Cretans; 1,000 neo-Cretans; 2,000 Thracians; 500 Lydian javelineers; 1,000 Kardakes; 2,000 Agrianian and Persian archers; 5,000 mixed Dahai and Kilikian light infantry; 5,000 mixed Medes, Kadousians, Karmanians and Kissians and 10,000 Arabs. The cavalry are described as being in two bodies, 2,000 and 4,000 strong respectively. The former most likely composed of the elite hetairoi and agema regiments (both normally represented as units of 1,000 each), the latter representing the line and light cavalry.
By 190 BC, Antiochos the Great was on the defensive in western Anatolia. Faced by two experienced Roman legions aided by Achaian and Pergamene allies, Antiochos issued an emergency call-to-arms and mobilised all available royal forces. The opposing sides faced off in the Hermos valley just to the north-east of the city of Magnesia and although the Seleukid right flank (once more led by Antiochos himself) carried all before it, the Romans prevailed on the Seleukid left and centre and the victory ultimately went to Rome. The resulting Peace of Apameia (ratified in 188 BC) was to have a far reaching affect on the course of Seleukid history. Appian and Livy provide complementary accounts of the Seleukid army at Magnesia which can be reconstructed as follows. Infantry: 16,000 phalangites (including 6,000 agyraspidai) fighting in the ‘Macedonian’ fashion; 3,000 Galatians; 3,000 Trallians, 1,500 Cretans, 1,000 neo-Cretans, 1,500 Karians and Kilikians; 6,700 assorted Phrygians, Lykians, Pisidians and Pamphylians; 2,500 Thysian archers; 8,000 Kyrtian slingers and Elymaiote archers and 2,000 Kappadokian auxiliaries furnished by Antiochos’ son-in-law, Ariarathes IV. The mounted arm was no less diverse: an uncertain amount of hetairoi cavalry; 1,000 agema cavalry; agyraspidai cavalry of uncertain strength; 6,000 cataphracts; 2,500 Galatian cavalry; a unit of Tarantines; 1,400 Mysian, Dahai, and Elymaiote mounted archers and what must have been a large host of Arab camelry. The Seleukid line was supported by numerous scythed chariots and 54 elephants. The total strength of the army is given at 70,000 men although only 56,100 of these are numbered among the contingents above. The hetairoi cavalry probably numbered 1,000 as they did at Daphne and the bulk of the remaining discrepancy was probably made up by the Arabs whose contingent at Raphia had numbered 10,000.
Following the cessation of the Sixth Syrian War, Antiochos IV Epiphanes organised a pseudo-Triumph at the Antiochene sanctuary-suburb of Daphne (167 BC), perhaps mimicking that held by L. Aemilius Paullus at Amphipolis. Whilst not representing an actual field army, Polybius’ list of the forces represented at the parade displays the military power available to the Seleukids and was surely meant as a clear reminder that even after the Peace of Apameia and despite the embarrassment of the Day of Eleusis, the Seleukid kingdom was not an entity to be trifled with. Represented in the pseudo-triumph were 5,000 agyraspidai reformed as imitation legionaries; a phalanx equipped in ‘Macedonian’ fashion (including un-reformed agyraspidai) 20,000 strong; 5,000 Galatians; 3,000 Thracians; 5,000 Mysians; 3,000 Kilikians; 1,000 hetairoi cavalry; 1,000 agema cavalry; a further 1,000 Median cavalry; a regiment of royal philoi, again 1,000 strong; 3,000 civic militia cavalry; an unspecified number of cataphracts; 140 scythed chariots and 36 elephants.
We can perhaps view the three lists as examples of the Seleukid army in different states of preparedness. We can assume that the Seleukid phalanx was composed of Greco-Macedonian colonists almost certainly supplemented by non-Greeks who had received a Greek education and training. Together with the hetairoi cavalry (described as “Syrian” at Magnesia, probably referring to Greco-Macedonian colonists) and assorted Greek mercenaries, these troops comprised the ‘Greek’ component of the Seleukid army. The bulk of the cavalry was composed of Iranians with the agema (forming the elite regiment) described as the best of the Medes and the surrounding peoples. The remainder of the army comprised national contingents from among the non-Greek populations who fought and we may imply, were educated, in their pre-Greek traditional manner, races such as the Kilikians, Elymaiotes and Arabs.
At Raphia, Antiochos the Great commanded a successful field army that appears to have been formed for the purpose of the Fourth Syrian War. Proportionately, 54.35% of his field army was sourced from Hellenised populations from both within and without the kingdom. The remaining 45.65% were non-Greeks. Antiochos’ army 27 years later at Magnesia on the other hand was hastily brought together in an emergency and we see the relative proportions (Hellenised, 31.19%: non-Greek, 68.81%) inversed dramatically. The proportion of the actual national contingents at Magnesia would almost certainly increase if we were provided with the number of Arabs in the army. At Daphne we see the return of similar proportions to Raphia with 62.5% Hellenised and 37.5% non-Greek forces. The rough proportions of the Seleukid standing army both before and after Apameia seems to have hovered between 50:50 and 60:40 in favour of the Hellenised elements of the kingdom. In times of crisis, additional national contingents could swell the army until they reached 70% or more of the total number of soldiers. At Raphia Polybius specifically states that the king was accompanied by interpreters when making his pre-battle orations and it can only be presumed that for the Seleukids this must have been common practice.
As the chronic war between the descendants of Seleukos IV Philopator and Antiochos IV Epiphanes progressed, the kingdom continued to lose territory and therefore recruitment potential, particularly in the East. The manpower shortage seems to have been filled at least partially by the increased presence of southern Syrians. We have already seen large contingents of Arabs serving under Antiochos the Great and it can only be presumed that such forces continued to appear in the armies of his successors. Alexander I was decapitated by an Arab prince, Zabdiel, in the service of Demetrios II and Ptolemy VI. Antiochos the Great had also realised the military potential of the (Babylonian) Jews and settled 2,000 Jewish families as military settlers in Phrygia (c.200 BC). In 152 or 151 BC Demetrios I Soter offered to enrol 30,000 Judaean Jews into his army although the high-priest Jonathan seems to have equipped a smaller force for Alexander I Balas instead. A contingent of 3,000 Jewish soldiers suppressed the Antiochene mob for Demetrios II and a great many more (led by the Jewish high-priest, John Hyrkanos I) accompanied Antiochos VII Sidetes on his anabasis (130-129 BC).
Like the Seleukid royal house, the Seleukid military exhibited a Hellenised core around which non-Greek auxiliaries were appended. Perhaps representing the limits of Hellenic manpower, the proportion of Greco-Macedonians in the army never reached as high as 65%. Naval forces appear to have been drawn almost exclusively from Kilikia and Phoenicia. Non-Greek elements were therefore of crucial importance to the kingdom’s defence and prowess and must have formed an integral part of the ‘Seleukid’ consciousness.
 Polybius Histories 5.79-87.
 Appian Syrian Wars 32-3; Livy History of Rome 37.40.
 The Daphne parade was either followed or preceded a similar celebration of the kingdom’s military vitality held at
Babylon (dated to 169 BC) commemorating the same campaigns, see and Horowitz 1997: 240-3; Linssen 2004: 119-20. It is probable that the event was not restricted to these two cities alone. Gera
 Polybius Histories 30.25; Aperghis 2004: 191.
 The scythed chariot corps, present also at Ipsos (301 BC), against Demetrios Poliorketes in Kyrrhestis (285 BC) as well as Magnesia (190 BC) and perhaps with Lysias in
Judaea (162 BC) testifies to the continued Seleukid willingness to experiment with traditional Persian arms, see Diodorus Siculus Library of History 20.113; Livy History of Rome 37.41-2; Plutarch Demetrius 28.3, 48.2; II. Maccabees 13.2; Bar-Kochva 1979: 83-4.
 Bar-Kochva 1979: 40, 45, 56, 296-7. Alexander the Great had provided Macedonian training and Greek education to 30,000 epigonoi, non-Greek youths who were to form the basis of his future phalanx (Arrian Anabasis 7.6; Diodorus Siculus Library of History 17.6; Plutarch Alexander 47.6; Quintus Curtius History of Alexander 8.5.1) and Eumenes and Antigonos Monophthalmos are both recorded as having employed pantodapoi, phalangites of mixed origins during the late fourth century BC, see Diodorus Siculus Library of History 19.27, 19.29; Griffith 1935: 48-9; Billows 1997: 357; Aperghis 2004: 195-6.
 I have classified the neo-Cretans as non-Greeks on the interpretation that they were a body of Asians equipped after the Cretan fashion (bow, sword and pelta) and used the same way (elite skirmishers). The designation neo-Cretan therefore being a pseudo-ethnic title. Spyridakis (1977) makes a good case for viewing the neo-Cretans as newly enfranchised non-Dorians from
Crete, comparable to Spartan Neodamodes. However, as the strength of the contingent is only ever listed as 1,000 strong, their nationality makes little impact statistically on the overall make up of the Seleukid army.
 Livy History of Rome 37.40; Polybius Histories 5.44.1; Bar-Kochva 1979: 45.
 Many of the forces (the Galatians, Mysians and Thracians, not to mention the elephant corps) marching at Daphne also clearly showed Antiochos Epiphanes’ disregard for the stipulations of Apameia which stated in no uncertain terms that the Seleukids were not to recruit north of the Taurus, nor were they permitted to own elephants, Livy History of Rome 38.38.
 Polybius Histories 5.83.7.
 Josephus Jewish Antiquities 13.118.
 Josephus Jewish Antiquities 12.147-53.
 I. Maccabees 10.36-7; Josephus Jewish Antiquities 13.38, 13.45-6.
 Josephus Jewish Antiquities 13.134-42. 13.249-50.