This will be apparent if we consider the previous history of the Church during the first half of the fifteenth century, when the conciliar authority was again invoked to regulate the Papal See and to check Papal encroachments on the realms and Churches of the Western nations.

The removal of the Papal Court to Avignon, the great schism which resulted from this measure, and the dissent which spread from England to Bohemia at the close of the fourteenth century, rendered it necessary that the representative powers of Christendom should combine for the purpose of restoring order in the Church.

Four main points lay before the powers of Europe, thus brought for the first time into deliberative and confederated congress to settle questions that vitally concerned them.
The most immediately urgent was the termination of the schism, and the appointment of one Pope, who should represent the mediaeval idea of ecclesiastical face to face with imperial unity.

The second was the definition of the indeterminate and ever-widening authority which the Popes asserted over the kingdoms and the Churches of the West.

The third was the eradication of heresies which were rending Christendom asunder and threatening to destroy that ideal of unity in creed to which the Middle Ages clung with not unreasonable passion.