The recital of this despatch threw the Parthian monarch into extreme perplexity. He did not believe that the proposals made to him were serious, or intended to have an honorable issue. The project broached appeared to him altogether extravagant, and such as no one in his senses could entertain for a moment. Yet he was anxious not to offend the master of two-and-thirty legions, nor even to give him a pretext for a rupture of amicable relations. Accordingly he temporized, contenting himself with setting forth some objections to the request of Caracallus, and asking to be excused compliance with it. “Such a union, as Caracallus proposed, could scarcely,” he said, “prove a happy one. The wife and husband, differing in language, habits, and mode of life, could not but become estranged from one another. There was no lack of patricians at Rome, possessing daughters with whom the emperor might wed as suitably as the Parthian kings did with the females of their own royal house. It was not fit that either family should sully its blood by mixture with the other.”
There is some doubt whether Caracallus construed this response as an absolute refusal, and thereupon undertook his expedition, or whether he regarded it as inviting further negotiation, and sent a second embassy, whose arguments and persuasions induced Artabanus to consent to the proposed alliance. The contemporary historian, Dio, states positively that Artabanus refused to give his daughter to the Roman monarch, and that Caracallus undertook his expedition to avenge this insult; but Herodian, another contemporary, declares exactly the reverse. According to him, the Roman Emperor, on receiving the reply of Artabanus, sent a new embassy to urge his suit, and to protest with oaths that he was in earnest and had the most friendly intentions. Artabanus upon this yielded, addressed Caracallus as his son-in-law, and invited him to come and fetch home his bride. Herodian describes with much minuteness, and with a good deal of picturesque effect, the stately march of the Imperial prince through the Parthian territory, the magnificent welcome which he received, and the peaceful meeting of the two kings in the plain before Ctesiphon, which was suddenly interrupted by the meditated treason of the crafty Roman. Taken at disadvantage, the Parthian monarch with difficulty escaped, while his soldiers and other subjects, incapable of making any resistance, were slaughtered like sheep by their assailants, who then plundered and ravaged the Parthian territory at their will, and returned laden with spoil into Mesopotamia. In general, Dio is a more trustworthy authority than Herodian, and most moderns have therefore preferred his version of the story. But it may be questioned whether in this particular case the truth has not been best preserved by the historian on whom under ordinary circumstances we place less dependence. If so disgraceful an outrage as that described by Herodian was, indeed, committed by the head of the Roman State on a foreign potentate, Dio, as a great State official, would naturally be anxious to gloss it over. There are, moreover, internal difficulties in his narrative; and on more than one point of importance he contradicts not only Herodian, but also Spartianus. It is therefore not improbable that Herodian has given with most truth the general outline of the expedition of Caracallus, though, with that love of effect which characterizes him, he may have unduly embellished the narrative.
The advance of Caracallus was, if Spartianus is to be believed, through Babylonia. The return may have been (as Dio seems to indicate that it was) by the way of the Tigris, through Adiabene and Upper Mesopotamia. It was doubtless on the return that Caracallus committed a second and wholly wanton outrage upon the feelings of his adversary, by violating the sanctity of the Parthian royal sepulchres, and dispersing their contents to the four winds. These tombs were situated at Arbela, in Adiabene, a place which seems to have been always regarded as in some sort a City of the Dead. The useless insult and impiety were worthy of one who, like Caracallus, was “equally devoid of judgment and humanity,” and who has been pronounced by the most unimpassioned of historians to have been “the common enemy of mankind.” A severe reckoning was afterwards exacted for the indignity, which was felt by the Parthians with all the keenness wherewith Orientals are wont to regard any infringement of the sanctity of the grave.
Caracallus appears to have passed the winter at Edessa, amusing himself with hunting and charioteering after the fatigues of his campaign. In the spring he threatened another advance into Parthian territory, and threw the Medes and Parthians into great alarm. He had not, however, the opportunity of renewing his attack. On April 8, A.D. 217, having quitted Edessa with a small retinue for the purpose of visiting a famous temple of the Moon-God near Carrhaa, he was surprised and murdered on the way by Julius Martialis, one of his guards. His successor, Macrinus, though a Praetorian prefect, was no soldier, and would willingly have retired at once from the war. But the passions of the Parthians had been roused. Artahanus possessed the energy and spirit which most of the recent monarchs had lacked; and though defeated when taken at disadvantage, and unable for some months to obtain any revenge, had employed the winter in the collection of a vast army, and was determined to exact a heavy retribution for the treacherous massacre of Ctesiphon and the wanton impiety of Arbela. He had already taken the field and conducted his troops to the neighborhood of the Roman frontier when Caracallus lost his life. Macrinus was scarcely acknowledged emperor when he found that the Parthians were close at hand, that the frontier was crossed, and that unless a treaty could be concluded he must risk a battle.
Under these circumstances the unwarlike emperor hurriedly, sent ambassadors to the Parthian camp, with an offer to restore all the prisoners made in the late campaign as the price of peace. Artabanus unhesitatingly rejected the overture, but at the same time informed his adversary of the terms on which he was willing to treat. Macrinus, he said, must not only restore the prisoners, but must also consent to rebuild all the towns and castles which Caracallus had laid in ruins, must make compensation for the injury done to the tombs of the kings, and further must cede Mesopotamia to the Parthians. It was impossible for a Roman Emperor to consent to such demands without first trying the fortune of war, and Macrinus accordingly made up his mind to fight a battle. The Parthian prince had by this time advanced as far as Nisibis, and it was in the neighborhood of that city that the great struggle took place.
The battle of Nisibis, which terminated the long contest between Rome and Parthia, was the fiercest and best-contested which was ever fought between the rival powers. It lasted for the space of three days. The army of Artabanus was numerous and well-appointed: like almost every Parthian force, it was strong in cavalry and archers; and it had moreover a novel addition of considerable importance, consisting of a corps of picked soldiers, clad in complete armor, and carrying long spears or lances, who were mounted on camels. The Roman legionaries were supported by numerous light-armed troops, and a powerful body of Mauritanian cavalry. According to Dio, the first engagement was brought on accidentally by a contest which arose among the soldiers for the possession of a watering-place. Herodian tells us that it commenced with a fierce assault of the Parthian cavalry, who charged the Romans with loud shouts, and poured into their ranks flight after flight of arrows. A long struggle followed. The Romans suffered greatly from the bows of the horse-archers, and from the lances of the corps mounted on camels; and though, when they could reach their enemy, they had always the superiority in close combat, yet after a while their losses from the cavalry and camels forced them to retreat. As they retired they strewed the ground with spiked balls and other contrivances for injuring the feet of animals; and this stratagem was so far successful that the pursuers soon found themselves in difficulties, and the armies respectively retired, without any decisive result, to their camps.
The next day there was again a combat from morning to night, of which we have no description, but which equally terminated without any clear advantage to either side. The fight was then renewed for the third time on the third day, with the difference that the Parthians now directed all their efforts towards surrounding the enemy, and thus capturing their entire force. As they greatly outnumbered the Romans, these last found themselves compelled to extend their line unduly, in order to meet the Parthian tactics; and the weakness of the extended line seems to have given the Parthians an opportunity of throwing it into confusion, and thus causing the Roman defeat. Macrinus took to flight among the first; and his hasty retreat discouraged his troops, who soon afterwards acknowledged themselves beaten, and retired within the lines of their camp. Both armies had suffered severely. Herodian describes the heaps of dead as piled to such a height that the manoeuvres of the troops were impeded by them, and at last the two contending hosts could scarcely see one another! Both armies, therefore, desired peace. The soldiers of Macrinus, who had never had much confidence in their leader, were demoralized by ill success, and showed themselves inclined to throw off the restraints of discipline. Those of Artabanus, a militia rather than a standing force, were unaccustomed to sustained efforts; and having been now for some months in the field, had grown weary, and wished to return home. Macrinus under these circumstances re-opened negotiations with his adversary. He was prepared to concede something more than he had proposed originally, and he had reason to believe that the Parthian monarch, having found the Roman resistance so stubborn, would be content to insist on less. The event justified his expectations. Artabanus relinquished his demand for the cession of Mesopotamia, and accepted a pecuniary compensation for his wrongs. Besides restoring the captives and the booty carried off by Caracallus in his raid, Macrinus had to pay a sum exceeding a million and a half of our money. Rome thus concluded her transactions with Parthia, after nearly three centuries of struggle, by ignominiously purchasing a peace.
It might have been expected that the glory of this achievement would have brought the troubles of Artabanus to a close; and if they did not cause the pretender who still disputed his possession of the throne to submit, would at any rate have put an end to any disaffection on the part of the subject nations that the previous ill-success of Parthia in her Roman wars might have provoked. But in the histories of nations and empires we constantly find that noble and gallant efforts to retrieve disaster and prevent the ruin consequent upon it come too late. When matters have gathered to a head, when steps that commit important persons have been taken, when classes or races have been encouraged to cherish hopes, when plans have been formed and advanced to a certain point, the course of action that has been contemplated and arranged for cannot suddenly be given up. The cause of discontent is removed, but the effects remain. Affections have been alienated, and the alienation still continues. A certain additional resentment is even felt at the tardy repentance, or revival, which seems to cheat the discontented of that general sympathy whereof without it they would have been secure. In default of their original grievance, it is easy for them to discover minor ones, to exaggerate these into importance, and to find in them a sufficient reason for persistence in the intended course. Hence revolutions often take place just when the necessity for them seems to be past, and kingdoms perish at a time when they have begun to show themselves deserving of a longer term of life.
It is impossible at the present day to form any trustworthy estimate of the real value of those grounds of complaint which the Persians, in common doubtless with other subject races, thought that they had against the Parthian rule. We can well understand that the supremacy of any dominant race is irksome to the aliens who have to submit to it; but such information as we possess fails to show us either anything seriously oppressive in the general system of the Parthian government, or any special grievance whereof the Persians had to complain. The Parthians were tolerant; they did not interfere with the religious prejudices of their subjects, or attempt to enforce uniformity of creed or worship. Their military system did not press over-heavily on the subject peoples, nor is there any reason to believe that the scale of their taxation was excessive. Such tyranny as is charged upon certain Parthian monarchs is not of a kind that would have been sensibly felt by the conquered nations, for it was exercised upon none who were not Parthians. If we endeavor to form a distinct notion of the grievances under which the Persians suffered, they seem to have amounted to no more than this: 1. That high offices, whether military or civil, were for the most part confined to those of Parthian blood, and not thrown open to Parthian subjects generally; 2. That the priests of the Persian religion were not held in any special honor, but placed merely on a par with the religious ministers of the other subject races; 3. That no advantage in any respect was allowed to the Persians over the rest of the conquered peoples, notwithstanding that they had for so many years exercised supremacy over Western Asia, and given to the list of Asiatic worthies such names as those of Cyrus and Darius Hystaspis. It must, however, be confessed that the account which has come down to us of the times in question is exceedingly meagre and incomplete; that we cannot say whether the Persians had not also other grounds of complaint besides those that are known to us; and, more especially, that we have no means of determining what the actual pressure of the grievances complained of was, or whether it did not reach to that degree of severity which moderns mostly hold to justify disaffection and rebellion. On the whole, perhaps, our conclusion must be, that the best justification of the outbreak is to be found in its success. The Parthians had no right to their position but such as arose out of the law of the stronger—
The ancient rule, the good old plan,
That those shall take who have the power,
And those shall keep who can—