In a feudal society, centred on peronal bonds of mutual obligation. accounting for precise degrees of protection and fellowship can prove difficult. Loyalty in these circumstances can become a matter of extremes: alternative groups may exist, but lack of mobility will foster a personal sense of loyalty.
The rise of states (and later nation states) meant the harnessing of the "loyalty" concept to foster allegiance to the sovereign or established government of one’s country, also personal devotion and reverence to the sovereign and royal family.
Wars of religion and their interminglings with wars of states have seen loyalty used in religious senses too, involving faithful support of a chosen or traditional set of beliefs or of sports representatives. And in modern times marketing has postulated loyalties to abstract concepts such as the brand. Customer churn has become the opposite of loyalty, just as high treason once stood as the opposite of the same idea. Compare loyalty card.
Etymology and Semantics
The English word "loyalty" came into use in the early part of the 15th century in the sense of fidelity to one’s oath, or in service, love, etc; the later state-oriented sense appears in the 16th century. The Old French word loialté (modern French loyauté), comes from loial (loyal), Scots leal, Latin legalis (legal, from lex (law)). The word functioned in the special feudal sense of one who has full legal rights, a legalis homo being opposed to the "outlaw". Thence in the sense of "faithful", it meant one who kept faithful allegiance to his feudal lord, and so loyal to the ultimate temporal power.
Partly based on http://1911encyclopedia.org