Source:  47th Annual Report of the Deputy Keeper of the Public Records
Title:  Calendar of Patent Rolls; 6 Edward I, 1886, London, 278
Date:  1277-1278
Place:  Gloucester

20 November 1277 - 19 November 1278

m. 16d. (104). Longford near Gloucester and Purton (“Pyryton’”) (Glouc.); appointment of Solomon de Rochester and Master Thomas de Sodington to take the assise of mort d'ancestor arraigned by Alice de la Plock’ against William de la Plock’, the elder, and Robert de Pyryton, touching a messuage and land in.

Mort d'ancestor

In English law, the assize of mort d'ancestor ("death of ancestor") was an action brought where a plaintiff claimed the defendant had entered upon a freehold belonging to the plaintiff following the death of one of his relatives.

It was one of the so-called "petty assizes" established by the Assize of Clarendon by Henry IIin 1166 along with the Assize of Northampton (1176). Like the other two assizes, it was abolished in 1833.

Two early instances of such an action are recorded in feet of fine from the reign of King John for a family dispute between members of the de Brantingham family in Yorkshire in 1202.

On 22 August 1202, one Matilda (or Maud), daughter of John de Brantingham, brought an action under the assize of mort d'ancestor against her sisters, Mary and Alice de Brantingham. Less than four months later, on 1 December 1202, John de Brantingham, son of Haldane the Deacon (and not to be confused with the later John de Brantingham, a Yorkshire clergyman), brought a similar action against his three daughters.

Source: Wikipedia