The second phase was under Charles Martel, who in both civil conflict and wars along the southwestern and northeastern frontiers, began to use armored cavalry. This method of warfare was much more expensive than infantry combat, and relatively few warriors could afford to sustain themselves. Charles began to assemble his own retinues. He would personally support a portion of them by providing them shelter, food, and arms in his own residence. By far the larger group was granted lands to sustain them, called benefices, or fiefs (feodum). In both cases, these warriors became vassi dominici-- vassals of the lord based upon an oath of absolute fidelity. This oath made sense when there was no impersonal law common to all in the realm. Such oaths of vassalage most likely bonded lesser nobles to Charles and Pepin III as well. Consultation and consensus with these nobles was integral to the Carolingian rise, until Charlemagne was supreme.
The third phase was attendant upon Carolingian decline and foreign invasions from the 830s. In the political anarchy of civil wars and Viking-Magyar marauding, only armed force through mounted cavalry provided any law or protection. The central army that existed was often ineffective against Vikings. By the time the royal host had assembled, the enemy raid had already passed through, plundering all in its wake. Two dynamics played in to this phase. First, later Carolingians needed armed allies, both to fend off foreigners, as well as to provide militaries to combat their relatives. Thus, kings had to offer something in return for their services: land grants. Second, lesser folk--weaker counts, aspiring warriors, parish priests, and the remaining free peasants--were willing to submit to more powerful men, in hopes of protection or advancement in precarious times. All this contributed to a disbursement of political, legal, and coercive power. Put differently, any authority with a hope of effectiveness had to be local. Thus, varying hierarchies of lord-vassal relations emerged. The feudal process developed soonest and most thoroughly in the regions far from traditional Frankish lands, such as the Western Kingdom, Lorraine, and even Franconia. In these places kings would assign lands to powerful local dukes, who in turn would need to parcel out portions of their fiefs to intermediate warriors in vertical chains through society. At first, land grants were temporary, then given for a lifetime. By the tenth century, in most cases they had become hereditary, based on primogeniture. As it developed, the relationship between lord and vassal took on a more rigid form. If accepted by a lord, the prospective vassal would perform a ceremony whereby he swore fealty to his patron, establishing a personal relationship. Something called homage was associated with this. A term whose difference from fealty is still unclear, homage is thought to involve the acceptance of a fief in return for services, though homage was also performed by members of household retinue receiving no land. In the usual case where a lord was a vassal to a higher figure, the lesser lord's vassals were a boon to the superior leader. As mentioned, services in return for land was key. The nature of them varied from region to region. In every case military service was a component. A vassal was required to serve as much as necessary in defensive efforts for his lord. As regards offensive enterprises, there was usually an upper limit per year, often the forty days corresponding to the spring-summer campaigning season. Often, an added duty was to serve in the garrison of a lord's estate. Beyond this, attendance at the lord's court was necessary, depending upon the position of a vassal in the feudal hierarchy. While it allowed the lord to keep tabs on vassals, and provided him with a judicial corps, it also provided the vassal with an opportunity to have his own views heard, regarding potential campaigns, alliances, or even marriages. Any major project of a lord would require such consultation in order to be practicable. Finally, various ad hoc dues such as hospitality when the lord visited, provision of extraordinary resources at times, and the payment of relief, or a key-money of sorts, when an heir succeeded to a fief, were part of feudal society.
It is not clear that this was the best political arrangement for early-high medieval Europe. It legitimized the enduring personalism of legal relationships, as well as rampant inequality. Also, it was cultivated for the sole purpose of organizing warfare as a means of not just survival, but livelihood and usurpation of kingly authority. Still, it did provide a modicum of local security when far-off kings or senior lords could not. A local vassal was reasonably likely to care for his farms and his villages, as they provided him with sustenance. Thus, a total collapse of society was prevented, and the nuclei of later states were supported in feudal beginnings. Whereas the fourth phase of feudalism was its generalization to the point of no effective kingly power, or his demotion to a first among equals, the emergence of polities on feudal bases would be a fifth stage of feudalism. In the luckiest of cases, the proliferation of medium- and high-level lords allowed more opportunities for elite patronage of culture and arts.