The Wool Trade Hierarchy
From one sheep’s fleece to a merchant’s cargo.
Origin
Established through the medieval wool trade and regulated by the Statute of the Staple from 1354 onward.
The catch
The system begins with the clove of seven pounds, which is roughly the fleece of a single medieval sheep. Every unit above it is a multiple of one animal’s annual yield, which makes the whole hierarchy a way of counting sheep without counting sheep.
English wool underwrote a great deal of medieval royal finance, and the Lord Chancellor still sits on the Woolsack in the House of Lords as a reminder of where the money came from. The units were not merely commercial: export duty was levied on them, so a merchant and a customs officer had to agree on what a sack contained before anything could move.