This article is the first detailed examination of the English parishes and knights' fees tax of 1428, based upon parliamentary and exchequer material. It demonstrates that the house of commons insisted upon granting this novel tax, in place of a more financially burdensome fifteenth and tenth, during the financial crisis of 1427–8. The parishes and knights' fees tax was efficiently administered, notwithstanding some local complications, although its yield was not commensurate with the scale of the crown's financial needs by the late fourteen‐twenties. This provides a unique insight into the origins of the well‐documented late Lancastrian fiscal crisis.