Vatican City, February 21 - A key commitment the next pope must be willing to make is to greater transparency in the dealings of the Catholic Church, a Roman cardinal said Thursday. Pope Benedict XVI, who retires on February 28, set a standard for transparency that his successor must not only match but exceed, said Cardinal Angelo Comastri, archpriest of St. Peter's Basilica and the Pope's vicar for Vatican City. Other criteria for the selection of the new pope will be determined after prayer for God's guidance, said Comastri, one of the 117 cardinals that will elect the next pope. And it seems "too long to wait for March 15" to begin the conclave, since cardinals are already arriving prepared to begin the selection process, added Comastri. It is possible that Benedict is preparing a special statement that will allow the conclave to begin earlier than the traditional 15-day waiting period, since he is retiring and has given ample notice. Usually, popes die in office and so the waiting period was needed to allow cardinals to travel to Rome from around the world. But sources have said Benedict may order a tighter time line for this conclave. Comastri suggested the pope very deliberately chose the season of Lent for his retirement, "because it is a time of call to conversion and Pope Benedict XVI is therefore inviting all to a conversion of heart".