The fall of the Roman Empire in 476 AD created a political vacuum in Europe. There was severe political turmoil in Western Europe. The invasions of Magyars, Vikings, and Muslims caused great horror in Europe. The central authority became useless and people began to look for the protection towards the local rulers who could fight the invaders. These people who had local armies gained political strength.
The foreign invasions of Europe can be cited between 850-950 AD. In the midst of this turmoil arose the system of feudalism where lands were controlled by the feudals. The system was based on mutual obligations. The feudal would give military protection and land or fief to the vassals. As a result, the ordinary people got protection from the invaders. The vassals were bound to offer services as knights.
The castles of these Lords were known as manors. These lords themselves may become the vassals of a great Lord. In a completed feudal system, the king was at the top with his lands and under him were vassals upto the peasants who were serfs. The peasants were responsible for providing food to the Lord. In short, feudalism touched political, social and economic life of Europe during the middle ages.