In the final book of his three part series charting the rise and decline of the remarkable Seleucid Empire, John D. Grainger hammers out the pressing causes of the dissolution of the once great empire founded by Seleucus I Nicator. Among the many Hellenistic successor states established after the death of Alexander the Great the Seleucid Empire would most closely resemble the Empire of Alexander in geographical magnitude, and would maintain that integrity for most of its history.
Following the death of Antiochus III the empire slowly withered away amid uncontrolled internecine warfare. These wars were brought about by succession disputes that commenced after Antiochus IV usurped the throne. This event set forth a new succession norm – i.e. the only thing necessary to rule was a powerful army to back the claimant. These dynastic civil wars weakened the state enough to allow separatist movements on the edges of the empire to gradually snowball into legitimate states – e.g. Parthia, Bactria, and Armenia. Ultimately, the once great empire would shrink into a regional kingdom mostly encompassing Syria, and would remain this way until its conquest by the Romans.
“Seleukid disintegration, it must be noted, was unique among the fates of the Hellenistic kingdoms. Only Macedon was broken up, by the Romans in 167, and this was reversed within twenty years, first by the rebellion of the Macedonians and then by Roman annexation of the whole and its conversion into a single Roman province. The Attalid kingdom’s main regions were taken over complete by Rome, with minor regions being awarded to allies, and Egypt fell as a complete unit to Rome in 30 BC.
“Rome, it seems clear, had no part in this disintegration. Occasional Roman visitors arrived for over a century and more, inspected the kingdom, and then went away. Occasional Seleukid claimants or enemies turned up in Rome, were heard, and received no help.
“Partly the disintegration which the Romans found was due to the sheer size of the original kingdom, so that breaking off fragments – Baktria, Parthia, Asia Minor – did not seriously damage the essential heartlands of Syria, Babylonia and Iran. And partly it was due to the inability of the Seleukid kings to maintain control over the more distant parts of a kingdom which was 2,000km long and more, and which could only be crossed at the speed of a marching soldier. Or to put it the other way around: it was due to the ambitions of governors installed by these Seleukid kings, who were able to develop a local interest network which enabled them to strike for independence and make themselves into kings at a time of central government weakness.
“Until 175 the royal succession had been reasonably clear: the king nominated his successor, who was always his eldest surviving son, a practice which, having been followed for a century, might be considered to be a rule. Antiochos IV’s ambition broke that sequence when he murdered his nephew and stepson; it then became clear that the kingship was available to whoever could seize it.
“…the kingdom was doomed from the start. By basing his power on a very narrow population base, Seleukos I had made it certain that the first succession dispute – and there was bound to be one – would begin the process of collapse. And yet unless he had based his power on the Greek and Macedonian settlers he would not have survived and there would have been no kingdom. Without the promise of land and cities to live in, the settlers would not have come; and without the settlers Seleukos and his successors would not have a kingdom to rule. The essential basis in the kingdom, the unifying element, was the king. When disputes about the occupation of the throne arose, disintegration happened. The kings made the kingdom, held it, and let it fall. In its origins was the kingdom’s ending.
*All excerpts have been taken from The Fall of the Seleukid Empire 187-75 BC, Pen and Sword.