Roman trade with India through the overland caravan routes via Anatolia and Persia, though at a relative trickle comparative to later times, antedated the southern trade route via the Red Sea and Monsoons which started around the beginning of the Common Era (CE) following the reign of Augustus and his conquest of Egypt. Having extended the Empire's reach to the upper Nile, the Romans naturally encountered the great warrior trading nation of Axum (on the Red Sea, in today's Ethiopia) which had been trading with India and Egypt for several centuries.
Roman trade diaspora frequented the ancient Tamil country (present day Southern India) and Sri Lanka, securing trade with the seafaring Tamil kingdoms of the Chola, Pandyan and Chera dynasties and establishing trading settlements which remained long after the fall of the Western Roman empire. They also outlasted Byzantium's loss of the Egypt and the Red Sea ports (ca. 639-645 CE) under the pressure of Jihad and Islam, which had been used to secure trade with India by the Greco-Roman world since the time of the Ptolemaic dynasty a few decades before the start of the Common Era. Sometime after the sundering of communications between the Axum and Eastern Roman Empire in the seventh century, the Christian kingdom of Axum fell onto a slow decline and faded into obscurity in western culture, though it survived despite pressure from Islamic forces until the eleventh century, when it was reconfigured in a dynastic squabble.