(UPDATE) VATICAN CITY: Pope Francis opened on Wednesday a major summit on the future of the Catholic Church, with progressives hoping it would lead to more women in leadership roles and conservatives warning that church doctrine on everything from homosexuality to the hierarchy's authority is at risk.

Francis presided over a solemn Mass in St. Peter's Square to formally open the meeting, with hundreds of clergy from around the world celebrating on the altar before the rank-and-file Catholic laypeople whose presence and influence at this meeting marks a decisive shift for the Catholic Church.