Today marks the first official day of Lent for many Christians. It's also Ash Wednesday.

Black crosses will mark the foreheads of many Christians on March 1, signifying the start of the season.

What is Ash Wednesday?

Ash Wednesday kicks off a period of 40 days before Easter focused on spiritual purification and repentance known as Lent. The 40 days are representative of the 40 days Jesus spent in the wilderness being tempted. 

The use of ashes on Ash Wednesday comes from Biblical history. Job 42 records a conversation between Job and the Lord God. In verses 4-6 of the King James version, Job answers the Lord, “Hear, and I will speak: I will ask thee, and do thou tell me. With the hearing of ear, I have heard thee, but now my eye seeth thee. Therefore I reprehend myself, and do penance in dust and ashes.”

Esther 4:3, Daniel 9:3 and Jeremiah 6:26 also make reference coming to the Lord during penance (repentance) or times of great need in “sackcloth and ashes.”

“Lent” is an Old English that means “length,” referencing the lengthening of daylight hours for the coming spring, according to Dictionary.com. The name is of stark contrast to the Latin name for Lent, “Quadragesima,” which means “fortieth.”

The number “40” occurs many times in the Bible: the 40 days Moses spent on Mount Sinai with God, the 40 days and nights of rain in the great flood survived by Noah, the 40 years of wandering by the Hebrew people in the desert while traveling to the Promised Land, and more.

What do the black marks mean?

Those black marks are administered in the shape of crosses and a are a mixture of ashes, Holy Water and, sometimes, olive oil. The ashes come from the palms used in the previous year's Palm Sunday, the Sunday before that marks Jesus' entrance into Jerusalem where he was met with palm branches by believers.

As the priest or minister puts the ash on the person’s forehead, he, or she, says "Remember that thou art dust, and to dust thou shalt return" (Genesis 3:19) or "Repent, and believe the Gospel" (Mark 1:15).

Christians are encouraged to wear the ashes, which can be distributed on either their forehead or hand, until the ashes wear off as a public declaration of their faith.