In the Christian calendar, Holy Thursday - also called Maundy Thursday and, in the Eastern and Oriental Orthodox Churches, Great Thursday is the feast or holy day on the Thursday before Easter that commemorates the Last Supper of Jesus Christ with the Apostles. It is followed by Good Friday.
On this day four events are commemorated: the washing of the Disciples' feet by Jesus Christ, the institution of the Mystery of the Holy Eucharist at the Last Supper, the agony of Christ in the Garden of Gethsemane, and the betrayal of Christ by Judas.
The evening celebration of these events marks the beginning of what is called the Easter Triduum or Sacred Triduum.
The Latin word "triduum" means a three-day period, and the triduum in question is that of the three days from the death to the resurrection of Jesus.
In the time of Jesus, and still today in some cultures, such as the Jewish, the (24-hour) day was reckoned not from midnight, but from sunset.
The Last Supper was held at what present-day Western civilization considers to be the evening of Holy Thursday but what was then considered to be the first hours of Friday.
Its annual commemoration thus begins the three-day period or triduum of Good Friday, Holy Saturday and Easter Sunday, days of special devotion that celebrate as a single action the death and resurrection of Christ, the central events of Christianity.