For those who do not know, a little backstory.

Mardi Gras is a Southern institution. After the last Krewe marches on home, the last set of Mardi Gras beads is flung into the air at the final parade, and one last bite of King Cake is eaten, the solemnity of Ash Wednesday takes over.

Ash Wednesday marks the start of Lent, the sobering (in every sense of the word) 40-day period that leads up to the celebration of Easter. The days of Lent are filled with reflection, repentance, and restraint as religious-minded folks frequently give up something like alcohol or meat or some other habit or activity as a means of expressing their faith and penance.

The long period of reflection begins with Ash Wednesday when Catholics as well as Christians of other denominations head to church to have a priest apply ashes to their foreheads. The dark mark on the forehead is usually applied in the shape of a cross and is worn throughout the day as a public display of faith.

The ashes are meant to symbolize “penance, mourning, and mortality,” a sort of physical representation of the phrase ashes to ashes, dust to dust. According to TIME, “Centuries ago, participants used to sprinkle themselves with ashes and repent much more publicly, but the practice fell away sometime between the 8th-10th century before evolving into what it is today.” Now, ashes are worn one day a year by believers who want to show their faith.

So, if ashes are only needed once a year, where do churches or parishes get the ashes they need for Ash Wednesday services? According to the Catholic News Agency, traditionally the ashes are made from the palm fronds that were gathered up after Palm Sunday of the previous year. Some churchgoers burn their own palm fronds at home, while some churches buy from a religious supplier instead of burning their own.

Wherever the ashes come from the process is about the same: the palm branches are burned down to a fine ash and prayed over. In the United States the ashes are typically mixed with holy water or chrism oil (a scented olive oil) to create a light paste. In other parts of the world, per the CNA, sometimes dry ashes are sprinkled on the head rather than made into a paste.

In addition to wearing ashes on their foreheads, people observing Ash Wednesday will typically fast on the day, eating only one large meal or two small meals that traditionally do not contain any meat. It’s another way of showing that people are sorry for their sins and aware of their mortality, a certain end to the excesses of Mardi Gras.