Answer: The statement here is absolutely correct.
Step-by-step explanation: In order to understand that why this answer is correct, I will provide you with a little insight of the history. The term vassal originated with the emergence of feudalism in the middle ages, at that time all the land was the possession of the ruling Aristocrat. The Aristocrat will reward their lands to vassals expecting that they will protect the Aristocrat in return. Whenever, some vassal will fight for the Aristocrat, the Aristocrat will provide him with a land and expect him to protect the the Aristocrat for rest of his life.