These were "substitution" and "subinfeudation". These grants were in turn subject to subinfeudation. Others could arise by the principal lord's special grant, approved by the sovereign of subinfeudation. Further estates could be created out of these estates in a process called subinfeudation. This constant process of granting new tenures was known as subinfeudation. This favoured subinfeudation as opposed to outright sale of land. Through subinfeudation, the manorial structure of the Honour shifted over the course of nine centuries. Subinfeudation would prove problematic so was banned by the statute. The creation of subfiefs under a tenant-in-chief or other fief-holder was known as subinfeudation.