What was a person called who received land from a lord and owed him service in return?

Explanation

The relationship described here is an agreement between free men of standing: land is handed over, and in exchange the receiver owes service, most often service in arms. An unfree peasant is the closest trap, because both owed something for the land they used, but the peasant's duties followed from his standing as an unfree man rather than from any grant made to him.