Scutage

Scutage is the practice of landed nobles to pay there way out of military service. The rate is currently 400 crowns a year for a knights fee. Taking in to consideration that several fiefs are not a hole number of knights fees it is not surprising that several knights both pay some Scutage in addition to serving themselves.
The sheriff of the Haflings in Tir Caeau Euraidd provides an yearly Scutage of 20 000 crowns alone.