The Vatican closed the Sistine Chapel on Monday in preparation for the secret conclave where cardinals will gather to elect the next pope, following the death of Pope Francis on April 21 at the age of 88.

When the conclave begins, the cardinals will enter the chapel in a solemn procession to participate in the secretive process, believed to be guided by the Holy Spirit, to choose the new head of the Roman Catholic Church, which has over 1.4 billion members worldwide.

Pope Francis was laid to rest on Saturday after a grand funeral Mass held at St. Peter’s Square, attended by world leaders and hundreds of thousands of faithful. The official nine-day mourning period is still ongoing before the secret voting sessions formally commence.

The world now closely watches as the historic process to select the next pope unfolds.