Answer:
The campaign was heralded by the Battle of the Kalka River in May 1223, which resulted in a Mongol victory over the forces of several Rus' principalities. ... All Rus' principalities were forced to submit to Mongol rule and became vassals of the Golden Horde empire, some of which lasted until 1480
Explanation:
SLAVERY<span> was a central institution in American society during the late-18th century, and was accepted as normal and applauded as a positive thing by many white Americans. However, this broad acceptance of slavery (which was never agreed to by black Americans) began to be challenged in the Revolutionary Era. The challenge came from several sources, partly from Revolutionary ideals, partly from a new evangelical religious commitment that stressed the equality of all Christians, and partly from a decline in the profitability of </span>TOBACCO<span> in the most significant slave region of Virginia and adjoining states.</span>
It is primary because it is the official process of methodically collecting information about a certain topic in a specific time period
