For many Mardi Gras revelers, the day after Fat Tuesday is a somber day of religious and spiritual significance.

Fat Tuesday precedes Ash Wednesday, which is the first day of Lent.

Lent begins on Ash Wednesday and ends on the day before Easter. Only weekdays are included in Lent, meaning it is the 40 weekdays beginning with Ash Wednesday, then ending the day before Easter. Lent was born out of the traditions of early Christians, who fasted to commemorate the suffering of Jesus, according to A History of the Christian Church by Williston Walker.

The First General Council of Nicea in A.D. 325 decided that Lent should be 40 days. The number 40 was selected because the number has spiritual significance for both Jews and Christians in regard to preparing for events. The Jewish Bible, the Torah, says Moses was with God for 40 days and nights on Mt. Sinai in preparation for receiving the Ten Commandments.

The Lenten tradition of 40 days specifically derives from the book of Matthew in the New Testament, in which Jesus fasts 40 days and nights, and in Luke, which says Jesus was led into the wilderness by the Holy Spirit to fast and be tempted by the devil for 40 days.

The word "Lent" dates back to medieval times, and is ancient German for "springtime," which is when Lent and Easter takes place.

While some Protestants observe Lent, it is primarily a Catholic tradition.

In earlier years, Lent was a bleak period in which people were precluded from engaging in any pleasures in life to practice penitence and purification. In earlier years, people refrained from eating sweets and going to parties, which is why Mardi Gras came about. Mardi Gras was seen as the last big celebration before a somber season of self restraint.

Ash Wednesday's name is derived from the ancient practice of using ashes in times of penitence, which is mentioned in both the Jewish Bible and the New Testament.

There is mention of Ash Wednesday services as early as the 10th century. During Ash Wednesday services, worshippers have the clergy put crosses on their foreheads using ashes as a reminder of mortality and the need for contrition.

Historically, ashes came from the burning of palm leaves that were used in the previous year's Palm Sunday services.

Today, those who observe Lent usually refrain from one type of food or activity during the 40 days, and do not eat meat on Fridays.

This year, Lent begins on Ash Wednesday on March 5 and ends right before Easter on April 20.