mort d’ancestor (mor[t] dan-ses-t<<schwa>>r). [Law French “death of an ancestor”] Hist. An

assize founded on the death of an ancestor. — Also termed (in Scots law) brieve of mortancestry.

“Another of the petty assizes was that of mort d’ancestor, founded on the Assize of Northhampton 1176. The question in this assize was whether the plaintiff’s father (or other close ancestor) had been seised in fee — that is, of an inheritable estate — on the day he died, and whether the plaintiff was his next heir; if both questions were answered in the affirmative, the plaintiff was entitled to be put in seisin.” J.H. Baker, An Introduction to English Legal History 267–68 (3d ed. 1990).

[Blacks Law 8th]