Definition of Benefice from a modern
Catholic Encyclopaedia.

(Lat. Beneficium, a benefit)

Popularly the term benefice is
often understood to denote either certain property destined for the
support of ministers of religion, or a spiritual office or function, such
as the care of souls, but in the strict sense it signifies a right, i. e.
the right given permanently by the Church to a cleric to receive
ecclesiastical revenues on account of the performance of some spiritual
service. Four characteristics are essential to every benefice:

• the right to revenue from church
  property, the beneficed cleric being the usufructuary and not the
  proprietor of the source of his support;

• a twofold perpetuity, objective and
  subjective, inasmuch as the source of income must be permanently
  established and at the same time the appointment to the benefice must be
  for life, and not subject to revocation, save for the causes and in the
  cases specified by law;

• a formal decree of ecclesiastical
  authority giving to certain funds or property the character or title of
  a benefice;

• an annexed office or spiritual
  function of some kind, such as the care of souls, the exercise of
  jurisdiction, the celebration of Mass or the recitation of the Divine
  Office.

This last mentioned element is
fundamental, since a benefice exists only for the sake of securing the
performance of duties connected with the worship of

God, and is based on the Scriptural
teaching that they who serve the altar should live by the altar.

Innocent III declared the sole purpose of
the foundation of benefices was to enable the church to have at her
command clerics who might devote themselves freely to works of religion.

Medieval constructions:
Mortmain, Praemunire, Provisor.

Letter of 1231 –
restraints on Rome.

Benefices in 1374.