Odd how things come up together...
I had just finished West's book on Indo-European myth and in particular noted at the end of it his identification of the deep roots of the comitatus in Indo-European culture - the king as the leader of a band of warriors whom he attached via, essentially, handing out booty or providing the opportunity to pillage.
The next day I was reading a book dealing with (inter alia) the conversion of Anglo-Saxon England, and read: "Seventh-century English kings did not 'govern' in any sense that we should recognize today. Their primary business was predatory warfare and the exaction of tribute from those they defeated. The spoils of successful war - treasure, weapons, horses, slaves, cattle - were distributed to their retainers as payment for past and lien upon future loyalty."
So the pattern described above has deep roots in Indo-European culture. Traditional poetry, whether about the Trojan War or a successful cattle-raid, reflects this.
In Europe generally, it is the Twelfth and Thirteenth Centuries which see the movement away from this pattern, at least at the local leader level. Prior to that point it was common for leaders well below the level of monarch to carry out raids and low-level warfare against their neighbours; it is in this period that the state begins to exert its centralizing powers to curtail this activity. In areas where national borders were involved it persisted for rather longer (such as the Scots Borders). The general basis for lordship becomes, not the distribution of booty, but the conferring and defending of rights to land (or patents, or other privileges) which can generate a continuing stream of revenue for the holders.
(Booty doesn't entirely go away. Soldiers continued to be given the implicit, and sometimes explicit, permission to pillage on campaign, and even after it became entirely frowned upon (consider Wellington's army in the Peninsular War) remained (and remains) a problem. (How many Allied homes have "souvenirs", like the Roman bust discovered recently in Texas, picked up by soldiers in the Second World War?) But it was no longer the systematic basis of lordship.)