Jesus washing Peter's feet, by Ford Madox Brown
The word Maundy derives from the command or mandatum by Christ at the Last Supper, to love one another. The Gospels relate that on the eve of his Crucifixion,
Jesus Christ ate a meal with his disciples. After the meal, it is
recorded that Jesus washed their feet, and gave them the following mandatum
or command: "If I then, your Lord and Master, have washed your feet, ye
also ought to wash one another's feet. For I have given you an example,
that ye should do as I have done unto you."