Why was the feudal system implemented? ?

In its early stages, feudalism evolved not implemented. It was a system that developed by itself as a solution to the political vacuum and anarchy created consequent on the fall of the Roman Empire. People who had control over land controlled men living on these and organised and regulated life in the area, serving a sort of a government. The system grew more perfect in course of time to such an extent that Lords who conquered/acquired more lands extended this system to these lands. Gradually it became universal but with slight variations in different places. The system was not implemented but evolved, accepted and modified.