Sunday after Easter
The Sunday after Easter, marking the end of the first eight days of Eastertide, was traditionally known as Low Sunday. It was a day of reflection and calm after the festivities and excess of the Octave of Easter.
Historically, Easter began a period of celebration and feasting. The harsh restrictions of Lent were no longer in effect, and to celebrate the resurrection of Christ a week of gluttony and partying commenced. This reflected the older pre-Christian origins of April, where a whole month was dedicated to worshipping the goddess Ēostre. Low Sunday falls on the day Jesus supposedly appeared to doubting Thomas, where Thomas stuck his finger into the wound in Christ’s side.
You were, neophytes, high and proud; you must now be low and humble.John Brand, Observations on the Popular Antiquities of Great Britain
In contrast to the high or elevated feeling on the Sunday of Easter, Low Sunday was the first after a week where modesty would be shown. In some places voices would be lowered, heads bowed, and it would be acknowledged as a quiet day. During the Middle Ages, church parishioners would have only been baptised during the Octave of Easter, starting on Easter Eve and ending on Low Sunday, for which they would have worn white robes. It was also the last day a person could receive the Eucharist for Easter.
Low Sunday is no longer recognised, and instead it has been replaced with another day of celebration, though the tradition of feasting for the Octave of Easter has also passed.