Biography
Accession and the New Era Name
In 1251, Duan Xiangxing died, and Duan Xingzhi succeeded to the throne, adopting the era name Tianding in the same year.
The Mongol Campaign and the Fall of Dali
In the ninth month of the second year of Tianding (1252), Möngke Khan ordered his brother Kublai and the general Uriyangkhadai to lead an army against Dali, advancing in three columns—eastern, western, and central. Kublai personally commanded the central column, crossing the Dadu River in October 1253 and reaching the Jinsha River, where numerous chieftains submitted and suggested crossing by inflated hide rafts. The Mongol army accordingly crossed the river on rafts made of animal hides and arrived at Lijiang in Yunnan—the celebrated episode known in history as "Kublai crossing the river on leather rafts" (Yuan kua nang). Kublai first sent envoys to urge Dali's surrender, but Gao Taixiang, the de facto ruler of Dali, advocated resolute resistance and killed the envoys. In the twelfth month, the central column drove straight to Longshou Pass and on to the walls of Dali with virtually no resistance, while Uriyangkhadai's western column crossed the river to Tacheng, Judian, and Shigu near Lijiang, and the eastern column reached Chuxiong and Yao'an beyond the Jinsha River, encircling the capital.
Although Dali's military strength was by no means negligible, the Gao clan, in order to weaken the Duan clan and control the government, had kept the elite of the Dali army under its own command while building up its own regional forces, leaving the royal domain comparatively weak. Duan Xingzhi and Gao Taixiang led their troops out to give battle before the city walls, suffered a crushing defeat, and fled in different directions, allowing the Mongol army to take the Dali capital almost without effort. Kublai ordered Yao Shu to tear silk into banners inscribed "Cease killing" and post them through the streets, whereupon the troops and civilians were calmed; Yao Shu also collected the archives and records of Dali. The Mongol troops captured Gao Taixiang at Yaozhou; refusing to surrender, he was executed at the Wuhua Tower, exclaiming before his death: "The fortune of the Duan house cannot be reversed—it is Heaven's doing. To die as a minister for his sovereign is my allotted end." Kublai regarded him as a loyal minister and permitted his descendants to hold office hereditarily; the Gao family was later enfeoffed as native chieftains (tusi) in Yao'an, Heqing, and other places, succeeding for more than thirty generations until the "bureaucratization of native offices" (gaitu guiliu).
In the fourth year of Tianding (1254), Kublai returned north, leaving Uriyangkhadai to continue the campaign. In the autumn of that year the Mongol troops pursued Duan Xingzhi to Kunming and captured him alive. From its founding by Duan Siping to its fall under Duan Xingzhi, Dali had lasted 317 years through twenty-two generations; its five cities, eight prefectures, four commanderies, and thirty-seven tribal districts all passed under Mongol rule.
Submission to the Mongols and Administration of Dali
After his capture, Duan Xingzhi was sent north to the Mongol court for an audience with Möngke Khan. Möngke pursued a conciliatory policy, granted him a golden tally, and ordered him back to Dali to continue administering the former territories. Duan Xingzhi then served as a guide for the Mongol army in mopping up the remaining resistance in Dali, personally led troops in suppressing the uprisings of various peoples against Mongol rule within the former kingdom, and later took part in the Mongol campaign against Annam (northern Vietnam).
In 1255, under Uriyangkhadai's protection, Duan Xingzhi went with his uncle Duan Fu to pay homage to Möngke, received a golden tally, and was ordered back to Dali to pacify the region together with Uriyangkhadai and the Grand pacification commissioner Liu Shizhong. The following year he presented Möngke with a map of Dali, requested the pacification of all the tribes, and submitted a memorial on governing the people and establishing taxation; he was granted the title "Maharaja" (Moheluocuo) and placed in charge of the various Bai-Cuan and other tribes. Soon afterward, Duan Xingzhi and Duan Fu led twenty thousand Cuan-Bo troops as the vanguard, guiding Uriyangkhadai's campaign against the unsubdued tribes and taking part in the subjugation of Jiaozhi.
In 1257, Duan Xingzhi was appointed Grand Administrator of the eight prefectures of Zhongqing Circuit, becoming the first Grand Administrator of Dali appointed by the Yuan dynasty.
Death
In 1260 (the first year of Zhongtong), Duan Xingzhi set out north with Duan Fu, intending to pay homage to Kublai, but died of illness on the way. The Mongols sent envoys to offer condolences and conferred the posthumous title "Xiangyi Tianding Xianwang." The following year, Kublai appointed Duan Xingzhi's younger brother Duan Shi (Duan Shiqing) as the next Grand Administrator of Dali, who proved equally loyal to the Mongols and won Kublai's favor.