This article examines Mongol-Yuan influence on the emergence
of proto-Tai/Tai polities after c. 1260 in the upper Ayeyarwaddy (Irrawaddy)
and Mekong river regions using the Yuan History, a recently discovered tomb
inscription of 1461, and other Chinese and Tai sources. I make five arguments. The
first is that as a successor state the Mongol-Yuan gained possession of former Dali
kingdom territories in Yunnan and northern mainland Southeast Asia by restoring
political power to the deposed Duan royal family. The second is that the restoration
of the Duan aided the Mongol-Yuan advance into northern mainland Southeast
Asia along communication routes leading from western Yunnan to the upper
Ayeyarwaddy and Mekong river regions established during the Dali Kingdom
period. The third is that M ng2 Maaw2 (Moeng Mao, Chinese: Luchuan 川),
a large political Tai confederation in the western mainland, arose c. 1335-1350s
in the context of the expulsion of Mian power from the Upper Ayeyarwaddy by
the Mongol-Yuan during the 1280s, and after the garrisoned Mongol-Yuan troops
withdrew in 1303. The fourth is that the case of a Han Chinese man appointed to the
Pacification Office in Lan Na c. 1341 attests that the Duan family aided Mongol-
Yuan administration of northern mainland Southeast Asia by supplying lower level
personnel to staff the yamen of Tai rulers appointed as native officials. The fifth is
that, judging from the historical data, such yamen exercised limited influence as
catalysts of Tai polity building. These five arguments are linked. Taken together,
they demonstrate that available evidence does not substantiate Victor Lieberman’s
claim that the Mongol-Yuan “encouraged the creation of Tai client states” in the
upper Mekong by providing them with “new military and administrative models”
through their status as native officials. My conclusion is that notions of “patronage”
and “client states” are misleading because they downplay the centrality of the proto
Tai/Tai as agents navigating their own way to polity building; proto Tai/Tai agency
is verified by their ambitious acquisition of new skills, technologies and writing
systems.