Subinfeudation

The system which the feudal tenants introduced of granting smaller estates out of those which they held of their lord, to be held of themselves as inferior lords. As this system was procoed-ing downward 'ad infinitum, and depriving the lords of their feudal profits, it was entirely suppressed by the statute Quia Emptores, 18 Edw. I. c. 1., and instead of it alienation in the modern sense was introduced, so that thenceforth the alienee held of the same chief lord and by the same services that his alienor before him held.

Brown.