Events of the past decade have once again placed the Korean peninsula in the position of a buffer state where the wars of greater powers are focused. Historians will recall that Korea has had this role thrust upon her many times before. In recent times the peninsula was the battleground for the Sino-Japanese War of 1894-1895 while the opening battle of the Russo-Japanese War of 1904-1905, a naval action, took place off the present port of Inch'ŏn. As a result, a number of studies of the various aspects of modern Korean society, particularly in its contacts with the West, have been undertaken but little attention has been given to the evolution of that society. Yet it is only when this is studied for each period in Korean history that studies of contemporary Korean society can be approached in other than a limited sense.
The period encompassing the Mongol invasions of the thirteenth century and the subsequent establishment of Mongol military-administrative organs on the Korean peninsula was one of the important phases of transition in Korean history.
The development of any society is, of course, continuous, but for the purposes of study I have found it convenient to treat the subject at hand in two natural divisions. The Mongol invasions of Korea in the thirteenth century as a development in Korean history form the subject of the present study. It is my intention to treat, in a separate work, the full extension of Mongol control in Korea which followed the period of conquest and with which I have dealt only summarily if at all in these pages. For the period covered I have, however, considered the question of the form and nature of Mongol demands upon Koryŏ as well as the implementation of these demands as an illustration of Mongol methods of establishing control in and extracting wealth from conquered nations. The reciprocal of this was the Koryŏ response to Mongol demands and pressures which was obviously limited and guided by her internal situation as well as her external relations.
The Mongol conquest and subsequent occupation of Koryŏ represent but one phase in the development of the Mongol empire and in many respects the least known phase.