Most of the abuses of the fifteenth and sixteenth centuries might be
traced back to the decline of the papal power during the Avignon exile
and the Great Western Schism. When peace was restored to the Church,
and when the Popes might have done something for the revival of
ecclesiastical discipline, the advocates of the conciliar theory
blocked the way by their extravagant attacks on the Papacy, and by
their attempts to destroy the supremacy of the Holy See under the
guise of reforming the Roman Curia. Besides, it was impossible to
carry through any effective measures for the removal of abuses without
attacking what were regarded as vested interests, and the holders of
these interests were determined not to yield without a struggle. The
cardinals wished to restrict the rights of the Pope; the bishops
wished to reform the cardinals and the Papal Court; the Paris doctors
wished to reform the bishops and the regular clergy; while the regular
clergy traced all the evils in the Church to the indifference and
neglect of the secular priests. Unfortunately there was no man endowed
with the foresight and the courage of Gregory VII. to put his finger
upon the real cause of the downfall, namely the slavery of the Church,
and to lead a campaign for the independence of the spiritual power,
particularly for the restoration of free canonical elections.

At the Council of Constance everybody recognised the necessity of
reform, but the jealousies of the various nations, the opposition of
the interests concerned, and the fear of provoking a new schism, made
it impossible to do more than to adopt temporary expedients, which, it
was hoped, might give some relief. Decrees concerning exemption from
episcopal authority, the union of benefices, simony, tithes, and the
duties of the clerical state were promulgated in the fourteenth
session, and the other questions, upon which the different nations
could not agree, were to be regulated by Concordats with the Holy See.