What is "inquisition post mortem"

n. an local investigation, in medieval England, into the lands of a deceased person in order to discover what income and legal rights were due to the crown

An Inquisition post mortem (abbreviated to Inq.p.m. or i.p.m., and formerly known as an escheat) (Latin, meaning "(inquisition) after death") is an English medieval record of the death, estate and heir of one of the king's tenants-in-chief, made for royal fiscal purposes. The process of making such inquisition was effected by the royal escheators in each county where the deceased held land. The earliest inq.p.m. was made in 1236, in the reign of King Henry III (1216–1272), and the practice ceased c.1640, at the start of the Civil War, and was finally abolished by the Tenures Abolition Act 1660, which ended the feudal system.