With the dissolution of the Charlemagne's empire and the rise of the monarchies, the political and social organization of feudalism evolved in Western Europe. The three main pillars of feudalism are: the fragmentation of political power, public power in private hands, and the armed forces being secured through private contracts. Its basic essence is derived from the concept of granting of land in return for military service. It led to the formation of the hierarchy of power, where land constituted the principal form of wealth and defined the political, social, and economic structures. The roots of the feudal system lie in the 8th century, when Charles Martel granted his nobles, rights over tracts of land to yield the income with which they could provide fighting men for his army. The act of generosity had to be sealed with the oath of loyalty towards the benefactor. This led to the development of the relationship between lord and vassal and this is the heart of feudalism. With the lord giving the vassal an income-yielding fief (fehu-od in Frankish, the basis of the word 'feudal'), the vassal in return paid homage to the lord with his loyalty, thus formalizing the relationship. The Development of Feudalism in Europe With the attack of the Vikings from the north, the Magyars from the west, and Muslims from the south, the central authority broke down. Public functions, obligations, and privileges were taken over by individuals, operating under a variety of private hierarchical arrangements created by personal obligation. This led to the development of feudalism in Europe in the 10th century BC. The Feudal Pyramid In the Middle Ages, feudalism resembled a pyramid, with the papacy at the helm of the affairs. The King, who came next in the feudal structure pyramid, was answerable only to the pope. In turn, everyone under the king had to pay allegiance to him and he would in turn, grant the land to important nobles and the lesser powerful military men who were called the vassals. While the nobles swore to protect and serve the king, the vassals or the knights agreed to fight for the king in exchange for the land. The last in the pyramidal structure were the medieval serfs, peasants, or the villeins who worked on the land and were allowed to subsist only on what they grew. Most of them toiled hard in their lands, which they were not allowed to leave. The positive part was that it was possible for everyone to move higher up the ranks of the pyramid of feudal system and this is what everyone aspired to do. The knights who were valiant in the battlefields, aspired to join the nobility, and the powerful nobles aspired to become kings. As time passed, the pyramid became more complex and riddled with bureaucratic problems with the fiefs becoming hereditary. There was also a breakdown of the mutual ties between the lords and the vassals. This, along with the centralization of strong lordships, whether as kings (as in England and France) or territorial rulers (as in the holy Roman empire), led to the decline of medieval feudalism.