<論説>ウェスパシアヌス帝の東方政策 : ローマ帝国の再建と最盛への礎

Abstract

紀元一世紀後半のウェスパシアヌス帝治世は、従来、ローマ帝国西部が発展した時代と考えられてきた。だが、この時代、大きく外観を変えたのは東方辺境であった。本稿では、ローマ＝パルティア関係と属州カッパドキア＝ガラティアの成立過程との二点からこの時代の東方辺境政策の実体を考察した。その結果、この政策には、先行研究が重視したような、パルティアに対抗しての軍備増強という対外的、軍事的要素は小さく、内乱で疲弊した財政の再建という経済的、内政的側面が強かったことが明らかになった。単なる辺境政策ではなく、帝国東部全体の再編策の一環だったのである。さらに、東部再編が現地出身者の登用を促進したことは、東部上層家系が中央政界へ進出し、後のドミティアヌス帝期、さらには五賢帝期に元老院議員身分内で一大政治勢力を成す契機となった。ウェスパシアヌス帝の東方政策は、帝国東部を東方属州として地域的にまとまらせ、五賢帝期の最盛を支える礎を築いたのである。

The reign of Vespasian has been considered as an era of the development of the western part of the Roman Empire. But, the eastern part of the Empire is as important as the western part. For the basis of Vespasian's faction in the Civil War in A. D. 69 was in the eastern part, and during his reign, the eastern frontier of the Roman Empire was quite changed: the client kingdoms such as Commagene and Armenia Minor were incorporated into the Empire; Cappadocia was joined with Galatia and stationed by two legions. Concerning these changes, other studies have insisted that Vespasian merely intended to make a defence line. By offering reasons other than military aspects, I demonstrate the further significance of the eastern part for the Emperor Vespasian. In the first part of this article, the diplomacy between Rome and Parthia, the incorporation of Commagene, is examined. In Vespasian's reign, this kingdom was no longer a buffer state, but completely subordinated to Rome, so we can regard the incorporation as a domestic administration. Rome just managed to secure control of the west side of the Euphrates, trying not to arouse Parthia. It was not necessary for Vespasian to make a defence line so as to prepare for Parthia's attack. In the second part, I examine the reorganization of eastern Asia Minor, namely, the unification of Cappadocia and Galatia together with Armenia Minor. Most important is the fact that Vespasian did not send a legion to Armenia Minor until A. D. 75. That is to say, the incorporation of Armenia Minor was not done for a military purpose. Instead, I stress two reasons about the reorganization of this area. The first is the disturbance of the south-east coast of the Black Sea: this area was annexed only in A. D. 64 and a rebellion against Roman rule happened in 69; legions were necessary to maintain order. The second is the economic importance of Satala in Armenia Minor. It was located on the crossroads of two trade routes, one from the Black Sea, the other from Armenia Major. The incorporation of Armenia Minor seemed to help Roman finances. The same reason can apply to that of Commagene, which was famous for its wealth. In the reign of Vespasian, the imperial economy was impoverished by the Civil War, so its reconstruction was his urgent duty. He exploited the eastern part of the empire as the resource of reconstruction, which had no damages from the war. The eastern frontier was not excluded. Thus, Vespasian's eastern policy must be regarded not only as a military policy, but also as an economical one. Lastly, I also show the importance of the eastern provinces from the point of human resources. First, the reorganization of the eastern part might require much more cooperation with the eastern provincials. The senators from the east such as the adlecti of Vespasian were mainly employed. This policy resulted in the dramatic increase of senators from the east in the reign of Domitian. Secondly, the main supporters of Vespasian in the Civil War became powerful following his reign, replacing the previously powerful senators from the Julio-Claudian Dynasty. Most of these rising senators were engaged in the reorganization of the eastern provinces as governors, and were connected with some senators from the east by patronage. It probably contributed to the advance of the status of the senators from the east. The most distinct example is the connection between the family of Trajan and that of Quadratus. As we have seen above, Vespasian's eastern policy not only reconstructed the imperial finances, but laid the foundations of the Roman Empire in the second century.