Mardi Gras might be defined by its beads, parades and fatty foods, but the holiday filled with debauchery has pious roots. Fat Tuesday, held 46 days before Easter, began as a Catholic tradition of revelry before the austere season of Lent begins.

Fat Tuesday may mark a specific day, but it actually refers to a season that begins on the Christian holiday of Epiphany. The holiday, celebrated Jan. 6, is also known as Three Kings Day and commemorates the adoration of Jesus Christ by the Three Wise Men. The time between Epiphany and Mardi Gras is commonly referred to as Carnival, during which parades take place in Catholic strongholds like Brazil, Venice, Uruguay, Trinidad and Tobago, and New Orleans.

This year Mardi Gras falls on Feb. 17. Below are answers to three common questions about the religious significance of Mardi Gras:

How Did Mardi Gras Begin?

Like many Catholic holidays, Mardi Gras bears resemblances to ancient pagan rituals, particularly Saturnalia and Lupercalia. The former honored the god Saturn, an agricultural deity, and was marked by gift-giving, revelry and gambling. The latter was conducted in mid-February to honor Faunus, the god of fertility, which involved feasting, drinking and debauched behavior.  

When Rome was Christianized, the Catholic Church adapted popular pagan holidays into the new faith. Mardi Gras season became a time to celebrate before the 40 days of Lent marked by prayer, repentance and atonement. As Christianity spread throughout Europe and the New World, so did Mardi Gras traditions. The pre-Lenten festivals continue to be marked by drinking, dancing and feasting on fatty foods containing meat, eggs, milk and cheese – ingredients that are restricted during Lent.

What Is Shrove Tuesday?

Shrove Tuesday falls on the same day as Fat Tuesday. It is the day before Ash Wednesday when Christians are reminded they will soon enter a season of penance. “Shrove” comes from the word “shrive,” which means to confess. In the Middle Ages, Catholics began marking Shrove Tuesday as a time to confess their sins before Lent. Today, those who belong to the Catholic or Orthodox tradition confess to a priest, who then pronounces the absolution of their misdeeds. Some traditions including burning palm fronds from the previous year’s Palm Sunday to use as ashes on Ash Wednesday, the first day of Lent.

The day is dedicated to penitence to purify the soul and is celebrated with feasts before Lent begins. Some call Shrove Tuesday Pancake Day after the dish’s fat, butter and eggs – foods that are prohibited during Lent -- which are made and eaten during the day.

Which Denominations Celebrate Fat Tuesday?

While Mardi Gras began as a Catholic holiday, today most major Christian denominations celebrate it, in particular Methodists, Roman Catholics, Presbyterians, Anglicans, Lutherans and Episcopalians.

Mardi Gras has different names around the world. In Pennsylvania Dutch Country, it is known as Fastnacht. The Dutch call it Vastenavond. Denmark and Norway refer to it as Fastelavn.

In cities with large Polish communities, including Chicago and Detroit, the day before Ash Wednesday is called Pączki Day, during which Polish bakeries distribute the traditional doughnuts made of lard, sugar and eggs for free.