From the website BBC Religious
Today, the fourth Sunday of Lent is Mothering Sunday. Although it is sometimes confused with Mothers' Day it has no connection with the North American celebration festival of that name and predates it by centuries.
Traditionally, Mothering Sunday was a day when children, mainly daughters, who had gone to work as domestic servants were given a day off to visit their mother and family. Today it is a day when children give presents, flowers, and home-made cards to their mothers.
On most Sundays in the year worshipers in England attend the nearest parish or 'daughter church'. Centuries ago it was considered important for people to return to their home or 'mother' church once a year. So each year in the middle of Lent, everyone would visit their 'mother' church - the main church or Cathedral of the area.
The return to the 'mother' church became an occasion for family reunions when children who were working away returned home. And most historians think that it was the return to the 'Mother' church which led to the tradition of children, particularly those working as domestic servants, or as apprentices, being given the day off to visit their mother and family. As they walked along the country lanes, children would pick wild flowers to take to church or give to their mother as a small gift.
Another thought is that the name comes from one of the Bible readings for that day, which refers to motherhood in a different way. In Galatians 4:26 it says, “26But the other woman corresponds to the Jerusalem above; she is free, and she is our mother.”
Mothering Sunday was once known as Refreshment Sunday because the fasting rules for Lent were relaxed that day. The food item specially associated with Mothering Sunday is the Simnel cake (a fruit cake with two layers of almond paste, one on top and one in the middle). The cake is made with 11 balls of marzipan icing on top representing the 11 disciples (Judas is not included). Traditionally, sugar violets would also be added.
The name Simnel probably comes from the Latin word simila which means “a fine wheat flour” usually used for baking a cake. There's a legend that a man called Simon and his wife Nell argued over whether the cake for Mothering Sunday should be baked or boiled. In the end they did both, so the cake was named after both of them: SIM-NELL.