The event that marked the beginning of a long period of republican control is the civil war. A civil war is also known as an intrastate war. It is a war between organized groups within the same state or country or less commonly between two countries created from a formerly united state.
It was mainly "a. Genghis Khan" who <span>united and expanded the Mongol Empire, due mostly to his superior military skills, which allowed the Mongols to conquer vast areas of land. </span>
