Holy Thursday (the Mass of the Lord's Supper) commemorates the night Christ washed his disciples' feet and instituted the Eucharist and the priesthood (John 13:1-20; Luke 22:14-20). The liturgy ends in silence: the altar is stripped, the tabernacle left open and empty, and the faithful keep watch before a reserved sacrament — a vigil echoing Christ's agony in Gethsemane.
Tradition places the Last Supper in the Cenacle on Mount Zion in Jerusalem, a room identified since at least the fourth century. The same building is venerated as the site of the Pentecost descent and of the washing of the feet. The present room, a Crusader-era Gothic hall, stands above the tomb of David — a layering of sacredness that makes Mount Zion one of the densest pilgrimage sites in the Holy Land.
After the liturgy, the Blessed Sacrament is carried to an "altar of repose" and churches stay open late for adoration. At Rome's Archbasilica of St. John Lateran — the cathedral of the Pope, where the Holy Thursday Mass is celebrated with the cardinals — the washing of the feet is performed by the Holy Father himself, who washes the feet of twelve people, often prisoners or refugees, in imitation of Christ.
