The Main Sources
Cassius Dio and the Historia Augusta
To construct a narrative of the reign of Marcus is far from easy. No narrative history survives that remotely resembles Tacitus' Annals
. The most important source ought to have been the relevant part of the History of Rome
by the Greek senator Cassius Dio, covering the period from earliest times until his own second consulship in AD 229, in 80 books.1
Dio was well qualified to write about Marcus, being a younger contemporary and a senator. He must have been born about the year 164, since he mentions that he was designated praetor by the emperor Pertinax, that is, in 193, no doubt to serve in 194 (Dio 73.12.2). From this one can infer that he was then aged about 30 (cf. Dio 52.20.1–2 with Morris (1964)). Thus at the time of Marcus' death in 180, while not quite old enough to enter the pre-senatorial career, Dio would certainly have been well informed about the main events and issues of the day, especially as his father, Cassius Apronianus, was also a senator (PIR2
C 485). Dio was a great admirer of Marcus, as shown by the long final section of Xiphilinus' epitome of Book 71, on Marcus' death, with a summing up of his life, ending with the contrast between Marcus' reign and that of Commodus: ‘our history now descends from a kingdom of gold to one of iron and rust, as affairs did for the Romans at that time’ (Xiphilinus 267–68; Dio 71.33.42–36.4).
But for Marcus' reign, which he covered in his Book 71, Dio's History is only available in the 11th-century Epitome by Xiphilinus and in some Byzantine excerpts. Dio's Book 70, on the reign of Antoninus Pius, was already missing when Xiphilinus was composing his Epitome:
It should be known that the account of Antoninus Pius is not found in the copies of Dio, probably because something happened to the books, and hence the history of his reign is almost completely unknown.
He can only offer the information, repeated from his summary of Book 69, that Antoninus was adopted by Hadrian and became emperor, Hadrian's first choice Lucius Commodus (who had been renamed Lucius Aelius Caesar) having died before Hadrian himself; and that Antoninus insisted, against opposition from the senate, on Hadrian's deification, as a result of which he was given the name Pius. Dio is also cited for an alternative reason for the name, Antoninus' refusal to punish ‘many who had been accused’ (70.1.1–2.1).
In his summary of Dio's Book 69, Xiphilinus had reported how
Hadrian caused Antoninus, since the latter had no sons, to adopt both Lucius Commodus' son Commodus [who was renamed Lucius Verus on becoming emperor], and, in addition to him, Marcus Annius Verus, a grandson of Annius Verus, three times consul and city prefect. And while he was ordering Antoninus to adopt both, he preferred Verus on account of his kinship and his age and because he was already showing his very great strength of character, for which reason Hadrian used to call him ‘Verissimus’ [‘truest’], playing on the meaning of his name in Latin. (Dio 69.21.1–2)
Xiphilinus added that ‘the first part of Dio's account of Marcus Verus, Antoninus’ successor' was also missing:
what he did regarding Lucius, Commodus' son, whom Marcus made his son-in-law, and what the latter did in the war against Vologaesus, having been sent there by his father-in-law. Therefore I shall tell briefly what I have read about these matters in other books. (Dio 70.2.2)2
Xiphilinus' brief substitute, derived from ‘other books’, for the missing first part of Dio's Book 71 begins with the following: Antoninus' death after a 24-year reign; Marcus' accession and the appointment of his adoptive brother Lucius as co-emperor; and the latter's marriage to Marcus' daughter Lucilla and dispatch to the Parthian War. Next he reports how the Parthian king Vologaesus had begun the war by attacking and destroying a Roman legion at Elegeia and then invading Syria; how Lucius, based at Antioch, entrusted command to Cassius, who in due course advanced into Parthian territory and destroyed Vologaesus' palace; then that Lucius, who ‘took great pride in these exploits’, later plotted against Marcus but died from poison before he could achieve anything. Although none of this came from Dio, it is conventionally labelled Dio 71.1.11–3.11. Modern editors have tacked on to this two genuine passages from Dio, quoted in the Byzantine encyclopedia, the Suda: one is on Roman bridge-building, in this case carried out by Cassius; the other relates how Sohaemus, the king of Armenia, first installed by Lucius in 164, was re-installed by Martius Verus, governor of Cappadocia, to which is added a laudatory character-sketch of this general. The first Suda excerpt clearly comes from Dio's account of Lucius' Parthian war in the 160s, but the second one must refer to an episode in the 170s. It belongs in the same context as a report taken from Dio in one of the Excerpta Valesiana (no. 304; Dio 71.14.2), on trouble in Armenia caused by a satrap called Tiridates: he had threatened Martius Verus and was deported to Britain (see PIR2 M 348, S 761, T 239).
Apart from Cassius' bridge-building, only one other episode from the earlier part of Dio's Book 71, not available to Xiphilinus, is preserved in an excerpt. This relates the invasion of the empire by 6 000 Langobardi and Obii, their rout by cavalry under Vindex and infantry under Candidus, and the barbarians' subsequent negotiations with the governor of (Upper) Pannonia, Iallius Bassus. The episode was transmitted via Petrus Patricius (Excerpta de legationibusG 6; Dio 71.3.1a), and is datable to about 166 or 167, thanks to independent information about the careers of Vindex and Bassus (PIR2 M 22, I 4).
At all events, it is clear that Xiphilinus' epitome of Dio on Marcus' reign only covers events after the death of Lucius Verus, which occurred early in 169. The same seems to apply to the collections of excerpts from Dio, principally the Excerpta Ursiniana 56–66 and Valesiana 302–312b, as well as the other passages in Petrus Patricius, and a few more in the excerpta Salmasiana and Vaticana. Not all of the events in these excerpts are easy to date and the order in the editions by Boissevain or Cary (Loeb) is not always satisfactory. The parts of Xiphilinus derived from Dio's Book 71 begin with further, introductory comments on Avidius Cassius and on Marcus. Cassius
was ordered by Marcus to administer the whole of Asia, whereas Marcus himself spent a long time, so to speak his entire life, having Pannonia as his base, making war on the Danube barbarians, Jazyges [i.e. Sarmatians] and Marcomanni, one after the other. (Xiphilinus 259; Dio 71.3.12
Cassius' appointment ‘to administer the whole of Asia’ belongs to the 170s, and the proper context is the paragraph on Cassius' suppression of the Egyptian Bucoli (Xiphilinus 259–60; Dio 71.4.1–2).
Sandwiched between these two mentions of Cassius is Xiphilinus' account of the barbarian invasion of Italy and its repulse by Pompeianus and Pertinax (Xiphilinus 259; Dio 71.3.2–4). As Xiphilinus has no information from Dio about the time before Lucius' death, this demonstrates that the invasion was later than this, in 169 or 170. The only apparent difficulty is Xiphilinus' expression referring to the invaders as ‘also many of the Celts from beyond the Rhine’. ‘Celts’, as often in Greek writers, means ‘Germans’, but Dio or perhaps Xiphilinus probably just added ‘from beyond the Rhine’ to distinguish them from the Gauls: this did not mean that the invaders actually came from that area (see Zwikker (1941) 156f.). There is no good reason to doubt that the invasion in question was that by the Marcomanni and Quadi, otherwise known only from an episode in Lucian's Alexander (48) and a retrospective passage in Ammianus Marcellinus (29.6.1). As to the date, comparison with the Historia Augusta's treatment of Pertinax's role in the latter's vita makes the year 170 far likelier, Pertinax 2.4–5:
From there . . . he [Pertinax] was transferred to Dacia . . . and subsequently, through Claudius Pompeianus, Marcus' son-in-law, was appointed, to be, as it were, his assistant, to command detachments; in which post he won approval and was enrolled into the senate.
From the data in Pertinax's vita, his post in Dacia, which preceded his service under Pompeianus and was followed by a period without employment, can hardly be dated earlier than 169 (Alföldy (1987) 326ff.; Piso (1993) 117ff.).
As will be seen, virtually the whole of what remains of Dio's Book 71 dealt with warfare, most of it being Marcus' Danubian campaigns, apart from the brief mentions of the intervention in Egypt by Avidius Cassius and that by Martius Verus in Armenia; further, Xiphilinus also gave fairly full treatment to the rebellion of Cassius in 175 and its aftermath. His Epitome devotes most space to certain episodes: the death of the Guard prefect Vindex at the hands of the Marcomanni and their eventual defeat, giving Marcus the title Germanicus, and the revolt of the Egyptian Bucoli, suppressed by Avidius Cassius (259–60; Dio 71.3.5–4.2); Marcus' industriousness in dealing with court cases and his ill-health, and a battle with the Jazyges on the frozen river, with the concluding remark that ‘Marcus thus subdued the Marcomanni and Jazyges after many hard struggles and dangers’ (250–51; Dio 71.6.1–8.1); the battle of the ‘Rain Miracle’ against the Quadi, into which Xiphilinus inserted the Christian interpretation (260–62; Dio 71.8.1–10.5); the rebellion of Cassius and its aftermath, including Faustina's death, then Marcus' return to Rome via Athens and the renewal of the northern wars (262–67; Dio 71.22.2–33.41), followed directly by Marcus' death and a long summary of his life and reign (267–68; Dio 71.33.42–36.4). Xiphilinus (or the scribes) misplaced the second of these passages (250–51), as well as a shorter previous one with two anecdotes about the war (249–50): they precede a string of passages from Dio's Book 69 (252ff.) and Xiphilinus' substitute summary for the missing parts of Dio, Book 70 and the first part of 71.
Some information in parts of these Xiphilinus passages is repeated in the excerpta, particularly the Valesiana, of which nos. 302–312a deal with Marcus' reign. Only nos. 304, on the treatment of Ariogaesus, king of the Quadi (see below) and the Armenian satrap Tiridates (see above), 305, on Marcus' refusal to look at Cassius' severed head, 306, on his treatment of Cassius' supporters, and 310, on his godfearingness, add anything. No. 117 of the excerpta Salmasiana has a brief report of the auction of imperial property in Ad 169, given at a little greater length by Zonaras 12.1, both surely taken from Dio's Book 71, and best known from the detailed accounts in Eutropius (8.11) and the Historia Augusta (17.4–6, based on Eutropius, and again at 21.9). The most important excerpts are in the excerpta UrsinianaG, 57–66, which recount mainly diplomatic activity in the northern wars. The first, no. 57 (Dio 71.11.1–5), describes Marcus staying in Pannonia, receiving barbarian embassies. The Quadi sued for peace, which was granted, to prevent them joining the Marcomanni and Jazyges, and they handed back thousands of deserters and prisoners. Other peoples also surrendered; some supplied troops and others were allocated lands in the northern provinces and even in Italy – but those settled in Italy later seized Ravenna and were removed, which meant that Marcus did not settle barbarians in Italy again. In no. 58 (Dio 71.12.1–3), it is reported how the governor of Dacia Clemens attempted to manipulate two branches of the Vandals and on the unsuccessful mission to the Cotini of the ab epistulis Paternus. The next excerpt, 59 (Dio 71.13.1–4), records the Jazyges unsuccessfully suing for peace and Marcus' refusal to recognize king Ariogaesus; one of the excerpta Valesiana, 304, reports Ariogaesus' ev...