In feudal Europe, there was very little of what we would think of as “upward mobility”. Peasants were tied to the land; they weren't 'slaves' in the sense that we think of today, but they couldn't just decide to leave. read more
Craftsmen could become wealthy, being very good at whatever they did, and over a few generations and enough acumen, could almost reach the top. But peasants were landbound, in the early middle ages even literary. read more
This was not a caste society, and the means by which a peasant could raise himself in the world then were not all that different than they are today: hard work, thrift, connection building, and a healthy dose of luck. read more