Image: Silver denarius of Sextus Pompey. Sicily. 42-40 BCE. Iconography (obverse: lighthouse of Messina; reverse: the monster Scylla) represents Pompey's blockade.
From the perspective of a young scholar in the field of ancient history, the implications of this paper are thrilling due to their explanatory potential. The climatological teleconnections established in this paper enrich our narrative of a notoriously unstable and poorly understood period in the history of the Mediterranean and Near East. Specific instances of political opportunism such Sextus Pompey’s Sicilian revolt and blockade can be better understood within a broader framework of resource scarcity throughout Eurasia. Within this framework, formerly disjointed elements of the traditional narrative begin to fall into place. The pattern revealed by this new framework is one in which localized manifestations of resource scarcity and competition catalyze a breakdown in pan-Mediterranean political and economic networks and a resurgence of regional networks of mutual dependence in crisis conditions. Local opportunists profited from this breakdown by establishing control over regional networks by various means (by formal agreements, such as the partitioning of the empire under the Second Triumvirate, or by active sedition by force of arms, such as Sextus Pompey and Quintus Labienus). Ultimately, these regional power brokers fell one by one to a resurgent central power helmed by a coalition whose strategy correctly identified the conditions necessary for a new geopolitical equilibrium and succeeded in establishing these new conditions in the form of the Roman principate, the first phase of the Roman Empire.
By the time that Okmok triggered the global cooling event of 43-36 BCE, Rome had already been at war with itself for roughly half a century. It would be easy (and wrong) for historians to point at the cooling period as the primary driver in the conflicts that wracked the Mediterranean during the last decade of the Roman Republic, ignoring the earlier conflicts. The authors of this paper instead suggest a more complicated, heterogeneous impact on the politics of this period: the occasional disentanglement of regional powers from trans-regional struggles and the rise of regional opportunists testing the limits of new (or sometimes very old) power configurations. The handful of individual historical agents and events cited in this paper are a tiny fraction of the vast world system caught up in this transformation. Historians have much work to do.
The Eurocentric perspective of former generations occasionally allows the high drama of events in what it conceives of as the “central conflict” to overshadow other significant developments in the history of this period. Perhaps the worst-served by historians is the situation of Rome’s relations with its eastern neighbors. Rome tends to present on paper (and especially in maps) as a polity so extensive and powerful that it could afford to take a vacation from its foreign wars in order to wage internal conflicts with little threat from outside. At no time in Rome’s history was this the case. Yet in telling the story of the civil wars that followed the assassination of Caesar, we tend to neglect one international conflict that is particularly important to the framework of scarce resources, regionalism, and opportunism characteristic of this period: the Parthian Wars.
Ever since Roman legions appeared in the Near East in the early 1st century BCE, their generals had to contend with the Arsacids, a dynasty of steppe-nomads from Parthia (southeast of the Caspian Sea) who had succeeded in resurrecting the ghost of the old Persian Empire. Generals of the Late Roman Republic made or broke their careers fighting the Parthians in Syria and the Levant. Indeed, on the eve of his assassination, Caesar had been planning just such a campaign of revenge for the humiliation of his former political partner Crassus (the Parthians had executed Crassus, the wealthiest man in Rome, by pouring molten gold down his throat). This plan did not die with its architect. Throughout the civil wars of the 40s and 30s, Roman and allied forces clashed with the Parthians. In one of these conflicts, the legions of Caesar’s former rival Pompey teamed up with the Parthian king and completely overran Syria, Pheonicia, and eastern Asia Minor, capturing the eagle-standards of several Roman legions in the process. Mark Antony, having established a collaboration Cleopatra, drove back these incursions and began planning an invasion of Parthia itself. One of the great historical problems of this period is why Antony failed, and why no serious attempt was made to push the Roman border east for another hundred and fifty years. Antony’s legions had been fully supported by Rome’s eastern clients, in particular Cleopatra of Egypt and Artavasdes of Armenia. Yet Antony allowed his supply chain to be cut off in the mountains between Armenia and Media, and was unable to continue the campaign. He scapegoated the Armenian king, whose forces he led back to Alexandria to serve as substitute captives in a triumphal procession that plastered over the Roman defeat.
At this celebration, Antony delivered a decree that sealed the fate of his alliance with Octavian by bestowing the titles to Rome’s eastern client kingdoms on the children of Cleopatra. The decree conceived of a new empire with its capital at Alexandria, encompassing all the former domains of the Ptolemaic Kingdom as well as the vast former dominion of the Seleucids in Asia.
Antony’s transition from Roman imperialist to Hellenistic regionalist covers a period that perfectly coincides with the decade of global cooling initiated in 43 BCE. His shift in priorities makes little sense for a man who had once aspired to wield the powers of Julius Caesar over a unified Roman Mediterranean as it had existed in the 60s. However, in the context of a resource-poor, Balkanizing Mediterranean of the 40s and 30s, the security of a political configuration centered on the old Hellenistic core of Egypt and Syria must have appeared a much safer bet. Unfortunately for Antony, who was learning the new rules of the game as he went along, someone else had already read the signs and was in the process of codifying the new rulebook. Antony had underestimated Octavian.
Octavian had succeeded in stabilising the western provinces of the empire and employed xenophobic political rhetoric in turning the legions against the famous general. After defeating Antony and Cleopatra in battle, he fully reversed their policy in the east, brutally ending the line of the Ptolemies and with it the idea of a united Hellenistic super-state. He also made peace with the Parthians, securing the return of the Roman eagles and withdrawing claims to territory beyond the Euphrates. Roman legions would not invade Mesopotamia until the time of Trajan.
Octavian, newly christened Augustus, recognized the concessions that needed to be made in establishing a new equilibrium. The vulnerabilities engendered by Rome’s continuous expansion and the political turmoil it fostered at home were now plain to see. The climate anomaly caused by the Okmok eruption of 43 BCE may have temporarily broken the geographical capacity of the Roman political system, but through this the political chaos it empowered leaders who broke with the mold of the military strongmen who had presided over the civil wars of the first half of the 1st century. Augustus was the ultimate winner in the new political arena precisely because he did not emulate his adoptive father, the grand conqueror. If the team behind this new study is correct, we have the Okmok eruption to thank for that.
Author: Joe Morgan, Graduate Researcher (Yale University)