Another important but under-examined aspect of trade throughout greater Asia is the connection between maritime and overland trade. Overland trade routes were often complimented by sea routes; the two types of networks worked in tandem.
Between 750 and 1000 Arab traders from the Caliphate in Baghdad could travel by sea from the Persian Gulf through the Indian Ocean to the South China Sea or
cross by land through former Sogdian territory into China's western region. The settlements of Arab traders in Sri Lanka in this period resulted in the connection of long-distance trade between the Persian Gulf region and China's southern seaport of Nanhai (Guangzhou).
31 Further west along the South China coast was Hepu, often described the maritime gateway for merchants traveling to or from the easternmost sections of the overland Southwestern Silk Road.
32 Along the way several seaports acted as starting points for northerly connections to the prevailing East-West overland routes that flourished when inland empires were at peace; in turn, these gave way to sea routes when the peace was lost.
One such hybrid maritime-overland route involved Indian Ocean traders crossing the Bay of Bengal to land at the mouth of the Irrawaddy River and load or unload cargo that traveled the river valleys north to the southern spur of the Southwestern Silk Road mentioned above.33
Such trade links fits well into the general trend of "Southernization" described by Lynda Shaffer in world historical terms, as Indian Ocean trade by Arab, South Asian and Southeast Asian seafarers created alternate routes for the
12th-century East-West circulation of goods between South China and the Mediterranean region.
34 The important role maritime links played in sustaining overland routes through northern Southeast Asia into China's southern frontier until the end of the Song dynasty should not be ignored, just as we must keep in mind the complementary role played by Southwestern Silk Road in global connections.