Though Kublai was celebrated above all as a Chinese emperor, he also helped to form the political traditions of his own Mongol people. To him and to his adviser, the Tibetan grand lama ’Phags-pa, is attributed the development of the political theory known as the “dual principle”—that is, the parity of power and dignity of religion and state in political affairs. That theory was turned to practical account on more than one occasion in the subsequent history of Mongolia and, for example, underlay the constitution of the theocratic monarchy proclaimed in 1911, when Mongolia recovered its independence from China.

Kublai’s character is difficult to assess. The only personal account of him is by Marco Polo, and that work is more of a panegyric than a sober appraisal. Polo presents Kublai as the ideal of a universal sovereign. Yet he does not overlook his human weaknesses—above all, an indulgence in feasting and hunting, a complicated and expensive sexual life, a failure to exercise proper supervision over his subordinates, and occasional outbursts of cruelty.

Kublai’s career is noteworthy above all because of the way in which he interpreted—and finally failed to reconcile—his dual roles. Even a man of his energy, willpower, and political insight—ruling with the advantage of absolutism unfettered by the old bureaucratic apparatus of China—could not resolve the contradictions inherent in his situation. As it turned out, he became a Chinese emperor of the traditional type. China absorbed his interests and energies to the exclusion of the Mongol homeland, and for years he was actually engaged in civil war with rival Mongol princes of the steppes. Under him, China, and of course the privileged Mongols, enjoyed a brilliant spell of prosperity, but his politics, pursued with less skill by his successors, isolated the Mongols in China from their environment. Still, it was not until some 30 years after his death that any serious uprisings against Mongol rule were to occur in China. With the collapse of the dynasty in 1368, however, the Mongols withdrew to the steppes and never again played any role of more than local importance.