The central observance of Holy Thursday is the ritual reenactment of the Last Supper at Mass. This event is celebrated at every Mass, as part of the Liturgy of the Eucharist, but it is specially commemorated on Holy Thursday. Except for the resurrection on Easter, Holy Thursday is possibly one of the most important, complex, and profound days of celebration in the Catholic Church. Holy Thursday celebrates the institution of the Eucharist as the true body and blood of Jesus Christ and the institution of the sacrament of the priesthood.