In modern society, we commonly refer to social strata as a loose structure which varies from country to country and which, in most cases, is measured based on income and the habits which derive from it. I say loose because in modern times, although sometimes hard, it is fairly common that within a lifetime someone can easily step up (or down) not just by one, but possibly many, rungs on the social ladder.
During the medieval period, however, this was fairly difficult, if not utterly impossible. The feudal system was much closer to the caste system. Passing from one class to another was not just a matter of wealth, but also of social and/or legal contract. In addition to that, wealth accumulation was often impossible since people (peasants, serfs, slaves) could very likely spend their whole lives without ever seeing or using a single coin.
The power of surplus
We live in an economy of abundance and this social mobility we enjoy is only possible because of surplus. Surplus of commodities (grains, livestock, building materials etc.) leads to the accumulation of wealth. But historically, the greatest percentage of population was living most of their lives not in a state of poverty, but in an equilibrium (living hand-to-mouth) where they were able to produce only the food/materials required to ensure their survival (and sometimes not even that, which would lead to times of famine). The main reason for that was the fact that the Feudal system was a pyramid which exerted power by means of ownership of land; since the bottom of the pyramid (peasants, serfs) did not own land but were “serfs” of the land, they could not accumulate a surplus because of heavy taxation.
As with every system, the feudal system also had its exceptions.
Freemen, Vagrants and the Clergy
A freeman is probably what most of us would identify with most closely. Freemen were not part of the land, or bonded to it. They were paying, one or another, taxation for their right to use the lands they occupied, which went to the owner of the manorial house (Lord of the Manor). This taxation was in no way as steep as the price serfs would have had to paid (workdays, grain or military service), and the Freeman was also able to own much bigger areas of land. Freemen were the lowest class that could even remotely consider social mobility. Paying less tax (though usually still in grain rather than coin) and working larger sizes of land allowed them to accumulate a surplus of wealth, which could mean that their offspring might have been able to buy an apprenticeship (tradesman or merchant), essentially opening their way into a world no longer tied to the land. This could potentially lead to the accumulation of the next level of wealth, coin.
This category includes minstrels, jonglers and thieves, bards and all bandits. Vagrants of all sorts lived their whole life as outsiders, some prosecuted, others adored, but almost always treated with some level of suspicion. Vagrants were people not tied to the land or a lord of any kind, many of them living on the fringes of civilised lands, or travelling. Because of this nomadic lifestyle, vagrants paid no taxes and, more often than not, declared no fealty to any Lord or King. This social echelon is where the heroes of a medieval fantasy world typically begin their journey.
Clergy existed in parallel with the feudal class system, rather than integrated into it. Members of the clergy were, in many ways, exempt and were never tied to the land of a lord; instead, they followed the pyramid of the Church, and were tied to its bidding. The main difference between the two pyramids was the fact that, within the church, mobility had nothing to do with wealth (or so it was implied). Within the boundaries of the Church ascension into higher ranks was a matter of influence, which could be gained by acts of merit or political manipulation. Clergy served as the mouthpiece of God and, as such, enjoyed a status that allowed them free passage and certain privileges even for the lower ranks of the church.
The lowest ranks of clergy included vicars (not really clergy), friars (travelling preachers, often thought as vagrants of God; this is where a fantasy-world cleric-character would fit in), monks (scribes and workers of monastic orders) and the lower class of priests.
This article is part of series of articles which lays the foundation for the interpretation of the social stratification of a High Fantasy medieval kingdom. Later on, you will be able to find links to the articles supplementing and extending this series.