In the preceding chapters I have traced two phenomena that were clearly inseparable. The first was demographic expansion with an attendant extension of networks – networks of settlement and of communication – throughout the Quannan region. Rapid and persistent demographic expansion began in the late Tang dynasty and appears to have continued largely unabated throughout the tenth and eleventh centuries; by the twelfth century the pace of expansion had apparently slowed, and in the thirteenth century it actually began to reverse itself. Up to that time, however, it had forged networks of settlement and communication throughout the Quannan prefectures; only the interior reaches of Zhangzhou remained lightly settled and unconnected. The second phenomenon was an emerging commercialization that affected the entire range of economic activity in the Quannan region. This phenomenon had its origins in the ninth century; after growing in importance through the interregnum, it took full shape in the eleventh and especially the twelfth centuries.

The linchpin of commercialization was the South Seas transshipment trade through Quanzhou. A pattern of trade through the ports of Quanzhou first comes to our attention in the late Tang dynasty, but it did not develop as a regular phenomenon or as a determinant of the broader regional economy until later. The unusual politics of the interregnum led the autonomous and independent warlords of Quannan to facilitate and promote trade through their territory as a way of maintaining state revenues.