The Paschal Triduum is a three-day period in the Christian liturgical calendar that commemorates the passion, death, and resurrection of Jesus Christ. It begins on the evening of Holy Thursday with the Mass of the Lord's Supper, continues through Good Friday, and culminates in the Easter Vigil on Holy Saturday. During the Paschal Triduum, Christians participate in various rituals and services that reflect on the significance of these events. The Triduum is considered the most important time in the Christian year, as it celebrates the core beliefs of the faith, including the sacrifice of Jesus and the promise of eternal life through his resurrection.