Baldus was the master of Pierre Roger de Beaufort, who became pope under the title of Gregory XI, and whose immediate successor, Urban VI, summoned Baldus to Rome to assist him by his consultations in 1380 against the anti-pope Clement VII.
This project dated back to 1670, when it was instigated by the secretary of Propaganda Fide, Monsignor Baldeschi, who, along with Cardinal Altieri, were among his most influential friends and contacts in the city.