Western Europe during the Middle Ages used the economic system feudalism. Feudalism was implemented since Western Europe had a weak central government. Also it was implemented because of disjoint institutions within the society. The rise of feudalism in areas formerly dominated by Roman institutions meant the breakdown of central government; but in regions untouched by Roman customs the feudal system was a further step toward organization and centralization. The church also had a great influence in shaping feudalism. The church owned much land, held by monasteries, by church dignitaries, and by the churches themselves. Most of this land, given by nobles as a bequest or gift, carried feudal obligations.
The feudal system was an arrangement of rank resembling a pyramid. At the top of the pyramid was the king. In the feudal relationship the king was the lord of a group of dukes and counts who were his loyal subjects. Each of these lord was in turn lord to lesser lords, who had even less important lords. At the bottom of the pyramid were the knights, who had no lords. A lord was expected to serve his lord in war. A knight was expected to furnish only his horse and armor, but great lords had to supply hundreds of knights and men at arms. Aids, payments made by lords when their lord needed additional resources. An aid was to help ransom the lord when he was taken prisoner in war. Other aids were given when the lord's eldest daughter was married and when his eldest son became a knight.
Feudalism impacted Western Europe by making it more defendable to invaders. If Vikings invaded they were long gone before the government could respond. With Feudalism the lords could easily respond to invaders a protect Europe more efficiently. Also Feudalism impacted the church which became the real ruler over the king. People would pay for favors to be done or a spot in heaven which made the church very powerful. Feudalism impacted Western Europe in many ways as you can see....