to it. The Roman system of measurement was built on the Greek system with Egyptian influences. Much of it was based on weight. The Roman units were accurate and well documented. Distances were measured, and systematically inscribed on stone by agents of the government. A fairly standard and fairly stable and abundant currency, at least up to circa 200 AD, did much to facilitate trade. (Egypt had its own currency in this period and some provincial cities also issued their own coins.) Contacts with India and China Alexander the Great had conquered as far as India, and the Roman god Bacchus was also said to have journeyed there. The Far East, like sub-Saharan Africa, was a mysterious land to the Romans. India There was an Indian in Augustus's retinue (Plut. Alex. 69.9), and he received embassies from India (Res Gestae, 31); one which met him in Spain in 25 BC, and one at Samos in 20 BC. The trade over the Indian Ocean blossomed in the 1st and 2nd century AD. The sailors made use of the monsoon to cross the ocean from the ports of Berenice, Leulos Limen and Myos Hormos on the Red Sea coast of Roman Egypt to the ports of Muziris and Nelkynda in Malabar coast and. The main trading partners in southern India were the Tamil dynasties of the Pandyas, Cholas and Cheras. Meticulous descriptions of the ports and items of trade around the Indian Ocean can be found in the Greek Periplus of the Erythraean Sea. In Latin texts, the term Indians (Indi) designated all Asians, Indian and beyond. The main articles imported from India were spices such as pepper, cardamom, cloves, cinnamon, sandal wood and gems such as pearls, rubies, diamonds, emeralds and ivory. In exchange the Romans traded silver and gold. Hoards of Roman coins have been found in southern India during the history of Roman-India trade. Roman objects have been found in India in the seaside port city of Arikamedu, which was one of the trade centers. Pomponius Mela argued for the existence of Northeast Passage through the northward strait out of the Caspian Sea (which in Antiquity was usually thought to be open to Oceanus in the north). China There is suggestive archaeological evidence that Roman traders were present in Southeast Asia, which was roughly mapped out by Ptolemy in his Geography where he labelled the land bordering the Magnus