Celebrating the first vespers for Divine Mercy Sunday, Pope Francis formally will deliver the “bull of indiction” or proclamation of the extraordinary Holy Year of Mercy.

Portions of the document will be read in front of the Holy Door at St. Peter’s Basilica April 11, the Vatican announced. The Holy Door, usually bricked up, is opened at the beginning of a jubilee year. The Holy Year of Mercy is scheduled for Dec. 8, 2015, to Nov. 20, 2016.