Biblical scholar and Priest Lauren F. Winner told Time Magazine that celebrating Ash Wednesday is a relatively new thing.
She said: "The practice of Ash Wednesday dates back to the 11th Century.
"You see that in the book Daniel in the nine chapter there’s a line about associating fasting with ashes, so ashes are associated with penance, which is the dominant theme of Lent."
Why is Ash Wednesday celebrated?
Ash Wednesday marks the first day of lent, and in 2018 falls on February 14.It is an important day in the Christian calendar as it marks the first day of fasting, repentance, prayer and self-control that will be required during Lent.
Its official name is 'Day of Ashes', due to the mostly Catholic practice of rubbing ashes in the sign of the cross on people's foreheads.
Why do crosses get drawn on peoples' foreheads on Ash Wednesday?
Traditionally, ash is used to represent grief, so devout Christians will wear the cross on their head for the entire day to show their sorrow for Jesus' crucifixion.They also represent repentance and show that people have repented of their sins so that they can be prepared for a 'Holy death', like Jesus.
As priests draw the crosses on to people's foreheads, they say: "Repent, and believe in the Gospel".
The cross is a nod to the Biblical passage “For dust you are and to dust you shall return" (Genesis 3:19).
The ash used to draw the crosses come from the palms that were blessed the previous Palm Sunday, which is the Sunday before Easter, and is mixed with olive oil or water to make a thick black paste.
Palm Sunday was the day that Jesus made a triumphant entrance to Jerusalem as the self-declared King of Israel, an event that marks the beginning of the Passion.
The crowds of Jews who lined the streets as he rode through laid down their cloaks and palm leaves to make a carpet for Jesus and his humble steed - which is where the name Palm Sunday originates.