Answer: Kievan Rus is also called as the land of Rus. It is located in Russia.
Step-by-step explanation:
The internal cause of the down fall: The empire weaken by the collapse of the commercial trade with the Byzantine empire and this lead to major economic crises in 12th century.
The various rival regional powers were influencing the working of the state.
The external cause of the down fall: The Mongol invasion in 1240s caused the complete fall of the state.