Several strata of working class during central middle ages (~950AD to ~1300), which were based on land/means of production ownership:

An "upper class" that owned tools and had money to lend to others. Might have been able to buy land from nobility and/or break into nobility (some evidently escaped the bounds of peasantry and became accepted members of nobility). These people declined rapidly around 1000AD, but were still around (albeit in drastically smaller numbers) by...

Notes on Feudalism, pt. 1
Feudalism as defined politically and economically. Marx said somewhere something about serfs performing customary labor on lord's demesne; "The hand-mill gives you society with the feudal lord[...]."

Political (traditional) usage involves reciprical rights between lord (king) and vassals who receive land (fief) in return for military service. All fiefs owned by knights, not all knights owned fiefs (landless knights = knights bachelor). Vassal...

The State is a particular institution or structure that claims or is used to claim ultimate authority, or sovereignty, over a given area.

This definition acknowledges those moments in history where the ruling class literally was the State and those times when the State is structurally independent from them. For instance, in ancient Sumer or other land-based societies (feudalism, etc.), the powerful military dictators (the ruling class) who controlled vast territories were the ones...