More than a few blogs posted on the meaning of Maundy Thursday this morning. I here quote Witherington:
It actually comes from the phrase Mandatum Thursday, or loosely translated ‘mandate’ or ‘commandment’ Thursday. It refers to the commandment from John 13 which you see in the picture above. Unfortunately, it was assumed that John 13 is about what transpired on Thursday of Holy Week, but historically this is probably incorrect. There is not footwashing episode on Thursday according to all three earlier Gospels, and furthermore, the time reference at the beginning of John 13 suggests this event transpired earlier in the week.
Pope Francis plans to participate in a foot washing, as the BBC reports:
Pope Francis will wash the feet of prisoners in a youth detention centre near Rome on Maundy Thursday.
Even so, many (Protestant?) celebrations are not focused on the commandment. Witherington goes on:
Traditionally, Maundy Thursday (the English garbled form of the Latin), has been a day to remember the Last Supper, the prayer in the garden of Gethsemane, the betrayal with a kiss, the taking captive of Jesus, and his abandonment by the male disciples— betrayal, desertion, and a threefold denial are the coup d’grace. It is on any showing a somber season.