Maundy Thursday, also called Holy Thursday or Maundy Thursday, is the Thursday of Holy Week (the last six days of Great Lent preceding Easter), the first day of the Easter celebrations (Easter triduum). On this day, we remember the Last Supper and the establishment by Jesus Christ of the sacrament of the Eucharist - Holy Communion.
And while they were eating, Jesus took bread, and having blessed it, broke it, and giving it to the disciples, he said, Take, eat: this is my body. And he took the cup and gave thanks, and gave it to them, and said, Drink all of you out of it, for this is My Blood of the New Testament, which is shed for many for the remission of sins. (Gospel of Matthew 26:26-27)
In the morning, in the cathedrals, the bishops celebrate a special mass of consecration of the world. Priests during this Mass renew the vows they made at ordination.