After millions of years of formation, development, and evolution, ancient humans dispersed and settled around the world during the late Quaternary Ice Age, utilizing the land bridges formed by the ice age to connect the continents. As human populations collected fruits, tubers, and hunted, they gradually became familiar with the growth patterns of certain plants and the habits of animals, and began to plant crops and domesticate animals in a planned manner according to seasonal changes. Thus, the division between agriculture and animal husbandry emerged, and humans transformed from passive gatherers and hunters subject to the nature to active food producers. Two parallel worlds gradually formed on the Eurasian continent: the nomadic world and the agricultural world. However, these two worlds did not exist independently and peacefully, but rather as two sides of a contradictory movement, with conflicts, confrontations, communication, and integration. The basic melody and rhythm of the conflict and fusion between these two worlds is roughly as follows: initially, nomadic peoples, under economic pressure, infiltrated, raided, or plundered the periphery of the agricultural world, often causing local friction and small-scale wars. When nomadic people rose to power and became strong while the agricultural world was relatively weak, they invaded the agricultural world and migrated into it. Nomads who invaded the agricultural world with chariots and horses initially plundered and destroyed on a large scale, and even caused the destruction of a civilization in a certain region. However, “in the long period of conquest, the more barbaric conquerors, in the vast majority of cases, had to adapt to the relatively high ‘economic conditions’ that existed after the conquest; they were assimilated by the conquered, and most of them even had to adopt the language of the conquered.” When the conquerors were integrated into the civilization of the agricultural world and ethnic integration gradually completed, a new friction and conflict began to accumulate and brew in the nomadic world, and soon a new large-scale storm of impact came. After the previous invaders became the conquered of agricultural civilization, they often became the objects of the next round of impact. This cyclical conflict and fusion between the two worlds swept many ethnic groups into a macro-historical process, causing the spatial location of ethnic groups, the differentiation, recombination, and convergence of various ethnic bodies to constantly occur in ancient history on the Eurasian continent. This directly promoted the historical development process between regions and ethnic groups, making the history of ethnic groups, nationalities, and regions on the Eurasian continent increasingly connected to world history.