[5] Gregory XII was chosen at Rome on 30 November 1406 by a conclave consisting of only fifteen cardinals under the express condition that, should Antipope Benedict XIII (1394–1423), the rival papal claimant at Avignon, renounce all claim to the papacy, he would also renounce his, so that a fresh election might be made and the Western Schism (1378–1417) ended.

[4] The two claimants opened wary negotiations to meet on neutral turf at Savona in Liguria, but soon began to waver in their resolve.

[4] The cardinals of Gregory XII openly showed their dissatisfaction at this manoeuvring and gave signs of their intention to abandon him.

Meanwhile, Gregory XII stayed in Rimini with the family of his loyal and powerful protector, the condottiero Carlo I Malatesta.

At the fifteenth session, 5 June 1409, the Council of Pisa declared that it deposed both Gregory and Benedict as schismatical, heretical, perjured, and scandalous; they pronounced that they had elected Alexander V (1409–10) later that month.

[7] Gregory XII, who had meanwhile created ten more cardinals, had convoked a rival council at Cividale del Friuli, near Aquileia; but only a few bishops appeared.

Until the mid-20th century, the Annuario Pontificio listed Gregory XII's reign as 1406–1409, followed by Alexander V (1409–1410) and John XXIII (1410–1415).