Crowds are beginning to gather in the central square of Castel Gandolfo to catch a glimpse of history: Two popes meeting for lunch and presumably discussing the future of the Catholic Church.

Pope Francis was to fly by helicopter Saturday to the papal residence in the Alban Hills south of Rome where Pope emeritus Benedict XVI has been living since resigning Feb. 28, the first pope to step down in 600 years.

Benedict's dramatic departure that day - flying by helicopter with his weeping secretary by his side and circling St. Peter's Square in a final goodbye - is one of the most evocative images of this remarkable papal transition.

The Vatican is downplaying the luncheon in keeping with Benedict's desire to remain "hidden from the world."