<論説>バクトリアにおける都市の廃絶と交易ルート (特集 : 滅び)

Abstract

本稿では、前二世紀から後一世紀にかけてのアフガニスタン周辺において、交易拠点となっていた都市の廃絶によってラピスラズリの交易ルートが変化する可能性を指摘した。最初に、ラピスラズリの交易拠点としても機能していたアイ・ハヌム遺跡と、その周辺地域の灌漑網の変遷を確認し、前三〇〇〇年紀から発展していたこの地域が、前二世紀半ばにおけるアイ・ハヌム遺跡の廃絶と軌を一にして衰退することを示した。続いて、『エリュトゥラー海案内記』の内容から、後一世紀半ばにはラピスラズリがインダス川河口のバルバリコンの港へともたらされていることを確認した。最後に、前一世紀半ばになってヒンドゥークシュ山脈中のバジャウル地域で、盛んにストゥーパを建造するアヴァチャ王家を名乗る集団が登場することに着目し、それが『漢書』西域伝の「大月氏の五翕侯」の配置とも密接に関連することから、チトラルを経由する新たな交易ルートの存在を想定した。

This paper indicates the possibility that trade routes for lapis lazuli changed due to the downfall of a city that had functioned as a trade center in Afghanistan and the region from the 2nd century BC to the 1st century AD. The paper first confirms various aspects of the Ai-Khanoum site, the location of a famed “Greek city” in Afghanistan, which was constructed in the early 3rd century BC. It is clear that the site functioned as a center of the lapis lazuli trade because archaeologists have excavated about 130 kg of lapis lazuli ore at the site. The ore must have been carried from the famous lapis lazuli mines around Sar-e Sang through the Kokcha River valley. Actually, the area around Ai-Khanoum had long been an important center for lapis lazuli trade from around 2500 BC. However, the study of the historical changes in the irrigated area around Ai-Khanoum reveals that the whole area around Ai-Khanoum declined simultaneously with the downfall of the site in the middle of the 2nd century BC. By examining “Periplus of the Erythraean Sea, ” I then confirm that lapis lazuli was carried to the Barbarikon port at the mouth of the Indus River in the middle of the 1st century AD. This means that the main trade route for lapis lazuli changed from the northern route (from mines to Ai-Khanoum, and to the western regions including old Mesopotamia) to the southern route (from mines to the upper Indus River beyond Hindukush, and to the lower Indus River). Unfortunately, “Periplus of the Erythraean Sea” does not include concrete information about the route across the Hindukush, so the route must be investigated by using various kinds of evidence. From the archaeological point of view, we should pay attention to the Apraca kings, who actively constructed Buddhist stupas in Bajaur, located amid the Hindukush mountains (the upper Kunar River), after the 1st century BC for possible evidence that might show the new route. As they made characteristic stone reliquaries with inscriptions sometimes including kings' names and years of the dedications, we can see that they suddenly became powerful and rich after the late 1st century BC. In addition, we should focus on the geographic arrangement of “Five Yabghus of Da Yuezhi” as another bit of evidence. The Five Yabghus were a kind of local governors who belonged to the Da Yuezhi (or Daxia, the area dominated by Da Yuezhi), and it is clear that Guishuang Yabghu, one of the five Yabghus, later evolved into the Kushan dynasty. According to some scholars, the five Yabghus were located in the mountainous eastern area of Hindukush, controlling the trade routes between China and the western regions including Bactria and Gandhara. Shuangmi Yabghu, located around Mastujii and Chitral, in particular might have had a close relationship with the trade route connecting the north and the south of Hindukush because it was the only Yabghu south of Hindukush. It is necessary to keep in mind that Bajaur, the area under the influence of the Apraca kings, lies next to the area controlled by Shuangmi Yabghu. This geographic relationship suggests that the Apraca kings might have emerged as a local power by engaging in trade with the Yabghus. In this way, various evidence indicates that the main trade route for lapis lazuli ran through the Hindukush mountains, especially through Chitral and the upper Kunar River valley, including Bajaur, after the 1st century BC. It is quite possible that the decline and fall of the Ai-Khanoum region, which had functioned as a trade center for lapis lazuli, accelerated the transition of the main trade route.