For most of the medieval period in most of Europe, the structure of society was determined by how hard it was to provide a steady food supply. Farming was not steady the way modern technology has made it, and the proportion of grain reaped to seed sown was usually very low. Because of this, particularly between the 8th and 11th centuries, the proportion of the population freed of all agricultural tasks was extremely low, and the materials of luxury or warfare were rare and highly prized.
The led to an initial aristocracy that was distinctly Roman, and usually existed because of slave labor, or indentured servitude. This kind of treatment led to a great deal of resentment, which is why often times men experienced in battle were hired by aristocracy and treated slightly better. Their protection was necessary, as was the extra muscle needed to enforce an unjust system.
At the top of the system were kings and emperors, but with the spread of Christianity, even they had to walk a fine line and be sure to exude a certain amount of priestly character. The Papacy would grow strong after successfully dealing with Atila the Hun, and the Pope would rise to great stations of influence before the Medieval age was over.
The Germans, on the other hand, lived a little differently. They had a more feudal society, similar to the one used by the highlanders in Scotland, where even without a king, they were warriors led individually by chiefs. Chiefs kept their power by proving over and over their ability to win battles, and therefore win the kind of loot needed to continuously buy and re-buy the loyalty of his followers. Some of the pagan kings (such as the Ynglings of Sweden) acted as priests, and a king's subjects usually followed him to the fount for baptism in the same way they followed him to war. Very special measures, including the earliest recorded Frankish consecration by a bishop, were required to legitimize the succession of a king from outside the ruling dynasty. In Catholic nations, this gave the Church enormous power and influence.
Free men were important to a society, and enjoyed a limited number of rights and comforts. Their lives were nowhere near the aristocracy, but they were certainly much better off than the common peasant who lived a life of back breaking toil, constant uncertainty, forced conscript into war, and usually early death. As bad as things were for the common man, they were even worse for a common woman. A married woman had no legal rights, and only a widow with land could hope to wield any type of authority. While that didn’t stop certain women from making their impact, even Joan of Arc was still a peasant, and her life ended burned at the stake. Society was rough for those not on top, and with all times in history, that was the majority of the people.