In Medieval times land was broken up into fiefs. But a fief was more then just a piece of land. A fief had to include at least one village with huts for the serfs, a manor house or castle for the noble, and land to grow or catch food.
A fief was not ownership. A fief was actually a loan from the king and the king could take it back.
Sometimes fiefs were given as reward for bravery in battle. To get a fief you had to promise the king several things. First, you would give your loyalty to the king; second, you would fight or send men to fight if the king needed them; third, you would provide money to ransom the king if he was captured; finally, you would take care of the serfs working the land.