Madonna and child
The way people thought about each other in the Middle Ages, everyone was involved in complicated systems of relationships with each other. Some people were still slaves, as in the Roman period, but not so many as before. Slavery was gradually dying out during this period.
The first relationships people had were with their own families. In medieval European families, most kids lived with their father and mother and brothers and sisters. Because people died young from diseases, a lot of kids also lived with other relatives, or just with an older brother or sister, because their parents had died. Most kids never knew their grandparents, who had died before they were born.
In the Middle Ages, hardly anyone went to school. Kids worked in the fields, or took care of younger brothers and sisters. A few children, usually from richer families, were given to monasteries or abbeys to be monks and nuns, and these children were sometimes taught to read and write. The children of very rich men and women sometimes had tutors at home.
Teenagers, around the age of twelve or thirteen, often went out to work for somebody else. Sometimes they worked for their neighbors, helping to plow the fields or take care of babies or animals. Sometimes they worked for richer families, as servants, as Chaucer did, for instance. Or they were apprenticed to learn a skill like weaving or blacksmithing. Many teenagers lived with the people they worked for.
Most peasants rented land from a richer man or woman who owned a big estate. They owed their landlord or landlady rent, and also a lot of other obligations. The peasants had to go to war with their landlord if there was a war, and they had to work a certain number of days every year for their landlady. Often peasants had to give their landlord or landlady a certain number of chickens or a certain amount of honey or spun wool or firewood every year. Even peasants who owned their own land often had some of these obligations to the nearest powerful person. In exchange, the powerful person was supposed to protect the peasants from invasions and from the king, and give them food when there was a drought, and enforce the law (which was mainly whatever he or she said it was).
Each of these powerful people, in turn, owed obligations to a more powerful person - each count or countess, for instance, owed obligations to a duke (or duchess) or an earl. If there was a war, the count had to go to the war with his peasants, to fight for the duke. And the count had to send valuable presents to the duke as well, every year. In exchange, again, the duke was supposed to protect the count.
Over everybody was the king or queen. Even the dukes and earls were supposed to fight for the king or queen and send him or her presents. But a lot depended on the king being strong enough to make them! Sometimes if the duke was strong enough, he just refused to come.
Some peasants also rented land from the Catholic Church, which owned about a third of the land in Europe during the Middle Ages. Their landlord would be a bishop instead of a count, and over the bishop was the archbishop, and then the cardinal, and over all of those the Pope in Rome. And some people became monks or nuns, in the service of the Church, instead of being peasants.