What is "the king's farmer"

Farmer \Farm"er\ (f[aum]rm"[~e]r), n. [Cf. F. fermier.] One who farms; as:

1. One who hires and cultivates a farm; a cultivator of leased ground; a tenant.
   --Smart.

2. One who is devoted to the tillage of the soil; one who cultivates a farm; an agriculturist; a husbandman.

3. One who takes taxes, customs, excise, or other duties, to collect, either paying a fixed annuual rent for the privilege; as, a farmer of the revenues.

4. (Mining) The lord of the field, or one who farms the lot and cope of the crown.

   Farmer-general [F. fermier-general], one to whom the right of levying certain taxes, in a particular district, was farmed out, under the former French monarchy, for a given sum paid down.

   Farmers' satin, a light material of cotton and worsted, used for coat linings.
   --McElrath.

   The king's farmer (O. Eng. Law), one to whom the collection of a royal revenue was farmed out.
   --Burrill.