The arch of Septimius Severus was constructed on the north-eastern edge of the Roman forum, in celebration of his campaigns against the Parthians. These had begun in 195 CE, following the defeat of Severus’s rival Pescennius Niger, who had been supported by various Eastern rulers, such as the small buffer kingdom of Adiabene, probably the Nabataeans, living in the provincial of Arabia, and the Parthian kingdom itself. The first campaign defeated the Persians, and extended Roman influence over the Arabs and Adiabeni (see Historia Augusta, Life of Septimius Severus, 18); the second campaign against Parthia was postponed until 197 CE, in order to deal with the threat posed to his reign by Clodius Albinus in Britannia, the remaining claimant to the imperial throne. Having been assisted by local rulers, such as Abgar IX, King of Osroene, who provided archers, and King Khosrov I of Armenia, who contributed money, in 197 CE, the emperor decided to move once more against the Parthians, crossing the Euphrates and campaigning in the area of Nisibis. In 198 CE, Septimius Severus’s army was successful in conquering and sacking the Parthian capital Ctesiphon and in annexing back Mesopotamia to the empire, as a new province, with Nisibis, by then a Roman colony, as its capital. However, the Roman army failed to conquer the Parthian’s fortified city of Hatra. In the wake of the victorious campaign, Septimius Severus was bestowed the title Parthicus Maximus, which had been previously assumed only by Marcus Aurelius and Lucius Verus after the victorious conclusion of their Parthian War (161-166 CE) (for recent further discussion, see Gradoni, “The Parthian Campaigns of Septimius Severus,” p. 3-24).

The date and purpose of the arch are clearly stated by the inscription that decorates both sides of the attic; it was dedicated to Septimius Severus and his sons by the Senate and the People of Rome to thank them for “the restored republic and the extension of the empire of the Roman people” (rem publicam restitutam imperiumque populi Romani propagatum). Although the relief detail clearly demonstrates the celebration of the conclusion to the Parthian campaigns, the ‘restoration’ to the Republic alluded also to the civil unrest that Severus had navigated in his pursuit of the principate, and his defeat of his rivals Pescennius Niger and Clodius Albinus (Newby, “Art at the crossroads,” p. 202-203). The celebration of a victory over a foreign enemy served to mask the fact that the emperor had risen to power in the wake of a vicious civil war, just as Augustus before him. Indeed, the association with the first princeps was clearly stated: the new arch was situated diagonally across from the triumphal Parthian Arch of Augustus, and on the same side of the forum as the Arch of Tiberius – erected in 16 CE to commemorate his recovery of the standards lost to Germanic tribes by Varus in 9 CE – demonstrating Septimius Severus’s desire to compare and associate himself with the first emperor (Kleiner, Roman Sculpture, p. 329). Both had risen to the imperial purple in the wake of a civil war, both established dynasties through their sons, and both were successful in defeating the Parthians. Then you should also highlight the similarities in the terminology of the inscription.

The relief decoration of the arch describes the importance of this foreign victory most vividly. On the lower pedestals supporting the columns that divide the three arched bays of the arch are pairs of Parthian prisoners in traditional costume, led by Roman soldiers (Kleiner, Roman Sculpture, p. 329). Above the smaller bays to the sides of the largest, central arch, are four panels of relief, whose scenes appear to show particular moments from both campaigns. Richard Brilliant’s seminal work on the arch has provided the most widely accepted interpretation of the scenes, due to his precise attention to their detail, much of which is today lost to environmental erosion. He proposed that the reliefs depicted a series of key moments from both the First and Second Parthian Wars, which were presented in chronological order following the seasons (Brilliant, The Arch of Septimius Severus, p. 115-120). The ‘first’ panel, located on the south-east side of the arch, appears to represent the siege of Nisibis during the first Parthian war in 195 CE; the panel can be divided in three registers, which should be read from the bottom up, beginning with the departure of the Roman army from the camp. The middle register depicts clashes between the Roman army and the Parthians, while the upper register on the right depicts the siege that led to the conquest of Nisibis, and the successive flight of the Parthian king, Vologases V. The upper register on the left depicts the adlocutio, or the ceremonial speech held before the battle, in which the emperor addressed the army (Brilliant, The Arch of Septimius Severus, p. 178-179).  The second panel, located on the north-east, can also be divided in three registers, and was identified by Brilliant as representing the city of Edessa and the submission of Abgarus  (Brilliant, The Arch of Septimius Severus, p. 179-180). The lower register depicts the departure of the Roman army, together with siege machines, towards Edessa; the city is depicted with its gates open, while various city dignitaries are ready to surrender to Rome. The central register depicts the surrender of Abgar VIII, King of Osrohene. The upper register on the right depicts the emperor, together with his staff, during a concilium, or meeting, held inside a military camp. The upper register on the left depicts the profectio, or the ceremonial departure of the Roman army for the campaign.

However, recent work by Maria Lloyd has suggested that Brilliant’s identification may be incorrect, noting that it would be inappropriate to depict Edessa – a city that was allied to Rome – on a victory monument. Most importantly, she has noted the presence of double-walls around the city depicted in the relief, and the presence of two siege machines connected with the army; the only city mentioned in the literary sources as having double walls is the city of Hatra (Cassius Dio, Roman History, LXXV.11.2; Herodian, Roman History, III.9.4), the siege of which Lloyd has identified in the north-eastern panel (Lloyd, “The Arch of Septimius Severus,” p. 553-557). In her interpretation, the panel reliefs are therefore not organised chronologically around the arch following the seasons identified by Brilliant, but rather in pairs of events, one from each of the campaigns, on each side of the arch, in order to remind the viewer of both wars; rather than requiring the viewer to walk around the arch in order to ‘read’ the progress of the wars, their entirety was presented on each side, with notable victories and successes visible from both eastern and western approaches (Lloyd, “The Arch of Septimius Severus,” p. 558).  

The panels on the western side of the arch, facing the Capitoline hill, are also problematic in their identifications. Brilliant believed that panel three, on the north-west, celebrated Roman victories in Seleucia and Babylon; the Roman army moves towards Seleucia, one of the Parthian capitals, in the lower register, with the central register depicting the surrender of the Parthian army, while the upper register depicts the triumphal entry of Septimius Severus into a conquered city, most likely Babylon (Brilliant, The Arch of Septimius Severus, p. 180-181).  However, the presence of a river in the relief perhaps suggests that the scene is in fact the victory at Ctesiphon; Brilliant had attributed this success to the final fourth panel of the arch, as the climax to the second Parthian War, but as the Roman army had arrived at the city by means of a river – as related by Dio and Herodian – the depiction of one here should be considered a significant addition (Lloyd, “The Arch of Septimius Severus,” p. 558). The fourth panel, on the south-western side, should – according to Maria Lloyd’s reconsideration of the arch – then represent an event from the first Parthian campaign. The panel has few distinctive features, depicting the escape of some inhabitants of a city, a siege engine, a city, and at the top of the fourth panel, a prominent scene of the emperor’s adlocutio, which Lloyd has interpreted as the occasion upon which Septimius Severus was awarded the titles Parthicus Arabicus and Parthicus Adiabenicus by the Senate (Herodian, Roman History, III.12; Llord, “The Arch of Septimius Severus,” p. 560). If Lloyd’s reading is correct, then the panels promoted the victories of both campaigns on each side of the arch, commemorating both wars in easy reach of the viewer.

However, as well as the commemoration of foreign victory, the arch served also a further important purpose, the celebration of the new dynasty. The arch is believed to have been surmounted by a bronze statue group of the emperor riding in the triumphal quadriga, with equestrian statues of his two sons and heirs, the elder Caracalla and the younger Geta, placed on either side. The text of the inscription also promotes this vision of the new dynastic power of the Severans; as well as dedicating the monument to the emperor, it offers it in thanks “to the Imperator Caesar Marcus Aurelius Antoninus Augustus Pius Felix” (Imperatori Caesari Marco Aurelio Luci filio Antonino Augusto Pio Felici). This was, of course, Caracalla, whose name at birth had been Lucius Septimius Bassianus, but which had been changed when his father was acclaimed emperor by the legions of Pannonia in 193 CE, to emphasise his connections with the Antonine dynasty (see Septimius Severus claims Antonine heritage). In 196 CE, three years after his father had been acclaimed emperor, the young Caracalla had been appointed both Caesar, and heir to the throne and princeps iuventutis, or the leader of the equestrian order, a further title that indicated his position as the primary heir of the emperor. Two years later, his younger brother, Publius Septimius Geta, was also appointed Caesar. Traces of the dowl holes at the end of line 3 and in line 4 of the inscription reveal that the line “the best and strongest princes” had replaced the earlier text et / Publio Septimio Lucii filio Getae nobilissimo Caesari (“to Publius Septimius Geta, son of Lucius, most noble Ceasar”) (Claridge, Rome, p. 75); although the line was removed in accordance with Geta’s damnatio memoriae in 212 CE, the arch’s inscription had originally celebrated both sons, as Augustus and Caesar respectively, in a clear statement of dynastic continuation. The link with the Antonines was emphasised through Caracalla’s nomenclature, and through the compositional and stylistic echoes of the relief decoration of the Column of Marcus Aurelius, which the panels of Severus’s arch sought to convey through its use of “vertical tiers to indicate spatial depth, and the isolation of the figure of the emperor through frontal depiction” (Newby, “Art at the crossroads,” p. 204).

The Arch of Septimius Severus in the Roman Forum therefore linked military victory and dynastic succession in an inextricable way; it promoted an image of the emperor that celebrated his success in foreign wars and the continued expansion of the Roman empire within sight of the Parthian Arch of Augustus that celebrated the very same, whilst also advertising his sons as his heirs and the dynasty upon which Rome’s future was to be based. His legitimacy was emphasised through the acclamation of Caracalla in the inscription as descended from the Antonines. Even the spandrels on both sides of the arch joined in this message; depicted within them were victories carrying trophies, with personifications of the Four Seasons immediately below, in a clear assertion that the emperor was victorious in all seasons. His sons and heirs were the means by which Rome and her empire would continue to flourish (Kleiner, Roman Sculpture, p. 331).