[3] The conclave, like its predecessor which had elected Eugene IV, was held in the Sacristy of the Dominican friars of Santa Maria sopra Minerva, even though many members of the College of Cardinals would have preferred to relocate to the Vatican.

[1] Prospero Colonna, the nephew of Pope Martin V and Protodeacon of the Sacred College, was regarded as the leading papabile at the start of the conclave.

Aeneas Silvius Piccolomini, who was one of the Custodians of the Conclave and is a principal source for the event, says merely that on Monday morning, March 6, there was some talk about the Archbishops, and then the scrutiny took place.

[4] On March 6, after the first of the two daily scrutinies, during which Colonna again received 10 votes, Cardinal Capranica addressed the conclave, reminding them of the various dangers facing the church, including the armies of the Alfonso, King of Aragon, which were sailing towards Italy, the (now unopposed) reign of Antipope Felix V, Duke of Savoy, as well as a certain "Count Francis"—imploring two more cardinals to throw their support to Colonna.

[6] Tommaso Parentucelli rose following this speech, and Giovanni Berardi (thinking that his colleague was about to give the election to Colonna) interrupted him and asked for a delay.