The fourth was a reform of the Church, considered as a vital element of Western Christendom, in its head and in its members.
The programme, very indistinctly formulated by the most advanced thinkers of the age, and only gradually developed by practice into actuality, was a vast one.

It involved the embitterment of national jealousies, the accentuation of national characteristics, and the complication of antagonistic principles regarding secular and ecclesiastical government, which rendered a complete and satisfactory solution well-nigh impracticable.

The effort to solve these problems had, however, important influence in creating conditions under which the politico-religious struggles of the sixteenth and seventeenth centuries were conducted.[17] The first Council, opened at Pisa in 1409, was a congress of prelates summoned by Cardinals for the conclusion of the schism.

It deposed two Popes, who still continued to assert their titles; it elected a third, Alexander V., who had no real authority.

For the rest, it effected no reform, and cannot be said to have done much more than to give effect to those aspirations after Church-government by means of Councils which had been slowly forming during the continuance of the schism.
The second Council, opened at Constance in 1414, was a Council not convened by Cardinals, but by the universal demand of Europe that the advances of the Papacy toward tyranny should be checked, and that the innumerable abuses of the Church and Papal Curia should be reformed.