Who and for what endowed people with feudal estates in Western Europe?

Initially, the feudal estates received for their service large military leaders under the princes and the first German kings. When the migration of Germanic tribes to the territory of the Roman Empire took place, a complete redistribution of lands was carried out. And the leader of each tribe, when settling somewhere, distributed his troops and the commander over them over the territory, so that it would not be required to bring huge reserves to one place. In return, the new feudal lords had to deduct part of the money and serve their leader.