VATICAN CITY (AP) — The Vatican crosses a key milestone Thursday in the runup to its 2025 Jubilee with the promulgation of the official decree establishing the Holy Year. It’s a once-every-quarter-century event that is expected to bring some 32 million pilgrims to Rome and has already brought months of headaches to Romans.

Pope Francis will preside over a ceremony in St. Peter’s Basilica for the formal reading of the papal bull, or official edict, that lays out the spiritual theme of hope for the year. The event also kicks off the final seven-month dash of preparations and public works projects to be completed by Dec. 24, when Francis opens the basilica’s Holy Door and formally inaugurates the Jubilee.

For the Vatican, the Holy Year is a centuries-old tradition of pilgrims visiting the tombs of Saints Peter and Paul, and receiving indulgences for the forgiveness of their sins in the process. For the city of Rome, it’s a chance to take advantage of some 4 billion euros in public funds to carry out long-delayed projects to lift the city out of years of decay and neglect.