How Medieval Society Worked

Only every nobleman: baron and above (viscount, count (Earl), Marquess, Duke, Prince, King, Emperor) had a Coat of Arms

UK still has a system of rules of who was entitles to Coat of Arms as well as register of all of them.

These are modern hereditary peers. House of Lords members. I think life peers are also entitled to Coat of Arms. There are 700 something of them in total.

To give you an idea how many of them there were. Earl of Count is a ruler of county. Both the UK and the US states are divided into counties, so you can count the total number of them. Each would be headed by an Earl with a Coat of Arms. Under Earl there will be number of Barons, each running a Manor in the county.

Manor is a medieval farming organization. Modern farming done by a single family with the help of machinery. However, in Medieval times, Manor lords only supervised the farming and actual labor was done by peasants.

However, being Lord of Manor was more of a reward for them.

Their real job was to be a low tier military commander. Somewhat of an NCO equivalent. They had to have military training and use income to maintain their military equipment and a horse. They also had to maintain a number of knights and their equipment as well. Together they were like a fireteam or a section of medieval army.

All nobility and knights were heavy cavalry, dudes in full plate armor, with lance on armored horses. Peasants were sometimes used as other types.

Earls and Dukes were higher tier commanders, captains and colonels maybe. Medieval army had less ranks compare to modern one. Kings were like generals.