Yang Liangyao’s Mission of 785 to the Caliph of Baghdād: Evidence of an Early Sino-Arabic Power Alliance?

The primary focus of this article is the information provided in a tomb stele (shendao zhi bei) of a Chinese eunuch, a certain Yang Liangyao (736–806), that will be comparatively analysed against the background of the political landscape under the Chinese Emperor Dezong (Li Gua; 742–805; r. 780– 805), and more specifically against the backdrop of the court’s politics in the face of Tibetan aggression. The stele inscription records the biography of Yang and claims that he was sent as an envoy to the Abbasids (Heiyi dashi; lit. “ Black-dressed Tajik”, i. e. the Arabs) by Emperor Dezong in 785. It seems that the mission was intended to ask the Arabs for military support against the Tibetans. The article intends to complement the preliminary work done on Yang’s mission by framing it within a broader context and by analysing the factors that may have prompted this trip. In particular, we want to address the question of why such an important diplomatic mission is neither mentioned in any other sources, and the question of why it has never been brought up in academic discourse. Although a clear indication that this trip even took place at all is absent in both Chinese and Middle Eastern historiography, there is no plausible reason to automatically rule out the possibility that the mission was carried out, or to assume that somebody might have faked such a story on an epigraphic document like this tomb stele. Historical circumstances and a comparison with information provided in other sources rather suggest that the mission was sent, perhaps even successfully, and there are also quite a few political reasons as to why the mission and information pertaining to Yang Liangyao himself were not included in the official accounts. The article will argue that particular historical circumstances suggest that his mission was very plausible; and that the decision to send him to the Abbasid caliphate to ask the Arabs for assistance in pushing back the Tibetans was at least in line with Emperor Dezong’s foreign policy strategy. We will also discuss questions connected with the possible identity of Yang Liangyao, something so far neglected in research.