VATICAN CITY – The Vatican was set to cross a key milestone on Thursday in the runup to its 2025 Jubilee with the promulgation of an 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 was expected to preside over a ceremony at 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 would also kick off the final seven-month dash of preparations and public works projects to be completed by December 24, when Francis opens the basilica's Holy Door and formally inaugurates the Jubilee.