In the wake of the Islamic conquests, trading activity between the Middle East and India appears to have expanded dramatically. Between the Hellenistic period and the first/seventh century, the Arabs had lost their predominance in this trade to the Ethiopians – Byzantium’s trading partners in the Indian Ocean – and, to an even greater degree, to the latter’s political and commercial rivals, the Sasanid Persians. The early Islamic conquests brought Byzantine/Sasanid rivalry to an abrupt end while bringing the Middle East into a single monetary exchange system and linking the Mediterranean to the Indian Ocean under the aegis of a single imperial polity. Gravitating towards Mesopotamia and the Persian Gulf, the trade with India became the major external source of wealth for Islam, at the same time that the overland route to China acquired much greater significance with the accession of the Tang dynasty in 618 CE. The Islamic trade with India was a trade in pepper (the ‘black gold of India’) and spices in the broadest sense, but included an almost infinite array of other items, from jewels to metallurgical products and ivory, to teakwood and textiles, which were exchanged against precious metals, horses and many manufactured products such as paper, glass and the like.