Shrove Tuesday was the last day before the beginning of Lent on Ash Wednesday, March 6 and noted in histories dating back to 1000 AD.
During the week before Lent, sometimes called Shrovetide in English, Christians were expected to go to confession in preparation for the penitential season of turning to God. One idea of the word "shrove" is from the old middle English word ‘Shriven’ meaning to go to confession to say sorry for the wrong things you’ve done.
It was the last chance to indulge yourself, and to use up the foods that aren’t allowed in Lent. In former days, there were many foods that observant Christians would not eat during Lent: foods such as meat and fish, fats, eggs, and milky foods. So that no food was wasted, families would have a feast on the shriving Tuesday, and eat up all the foods that wouldn’t last the forty days of Lent without going off. So on Shrove Tuesday, stores of dairy products were used up in the pancake mix. Pancakes are a comon way of using up fat. Also by giving up dairy products, people marked Jesus’ 40 days and nights in the wilderness.