By Elliot Williams*

VATICAN CITY — Saturday evening, in front of the Holy Door in the atrium of St. Peter’s Basilica, Pope Francis’ will give the archpriests of the major basilicas of Rome copies of his “bull of indiction,” or formal proclamation, of the Holy Year of Mercy. An aide will read portions of it at the door before participants process into St. Peter’s for evening prayer.

The Holy Door at St. Peter’s Basilica. (CNS/Paul Haring)

The site chosen for the brief rite was not made casually; the door symbolizes a passage or transition into a special year of evangelization and prayer.

Pope Francis will be back at the door Dec. 8 to formally open it and the Year of Mercy.

Popes typically announce a jubilee every 25 years, although extraordinary Holy Years have been proclaimed for special anniversaries — for example, a Holy Year was celebrated in 1983…