from
Bouvier's Law Dictionary, Revised 6th Ed (1856)
EXTENT IN CHIEF, English practice. An execution issuing out of the exchequer
at the suit 'of the crown. It is a mere "fiscal writ. See. West on Extents;
2 Tidd. Index.
2. When land was extended at a valuation too low, there was no remedy
at common law but to pay the money. 15 H. VII. Nor yet in chancery, unless
there was fraud, because the extent was made by the oath of a jury, and
deemed reasonable according to the writ of extent for that cause: otherwise
every verdict might be examined in a court of chancery. Crompt. on.
Jurisdic. 55 a.