Leaving Bologna, where he was elected, he went to Rome, and found there Louis of Anjou, who had brought the army from Provence, and coming to an engagement with Ladislaus, routed him.

But by the mismanagement of the leaders, they were unable to prosecute the victory, so that the king in a short time gathered strength and retook Rome.

Louis fled to Provence, the pope to Bologna; where, considering how he might diminish the power of Ladislaus, he caused Sigismund, king of Hungary, to be elected emperor, and advised him to come to Italy.

Having a personal interview at Mantua, they agreed to call a general council, in which the church should be united; and having effected this, the pope thought he should be fully enabled to oppose the forces of his enemies.
At this time there were three popes, Gregory, Benedict, and Giovanni, which kept the church weak and in disrepute.

The city of Constance, in Germany, was appointed for the holding of the council, contrary to the expectation of Pope John.