Ashes to Ashes

Ashes to ashes, dust to dust son, get where you're going by eternal combustion -Claude Clay, Town Undertaker from Tumbleweeds

Ashes started being used around 960 ad. In the 12th century the ashes began being made from the burnt palm leaves from the previous Palm Sunday.

Scriptural Basis

Ashes and/or Dust have been used since ancient times as symbols for both repentance and mourning, In some cases they have also been used for preparation. In 2 Samuel 13:19 we have Tamar, whose brother forced himself on her, and for her shame she rent her garments and put dust on her head. In Job 2:8 we have Job, afflicted by Satan with sores, sitting among the ashes. In Daniel 9:3 we have Then I turned my face to the Lord God, seeking him by prayer and supplications with fasting and sackcloth and ashes. The Maccabees, prepared for battle using ashes: "That day they fasted and wore sackcloth; they sprinkled ashes on their heads and tore their clothes" (1 Mc 3:47; see also 4:39). And in Matthew 11:21 Jesus says, "Woe to you, Chora'zin! woe to you, Beth-sa'ida! for if the mighty works done in you had been done in Tyre and Sidon, they would have repented long ago in sackcloth and ashes.”

LENT
Lent developed in the Church as the whole community prayed and fasted for the catechumens who were preparing for Baptism. At the same time, those members of the community who were already baptized prepared to renew their baptismal promises at Easter, thus joining the catechumens in seeking to deepen their own conversion. It was natural, then, that the Order of Penitents also focused on Lent, with reconciliation often being celebrated on Holy Thursday so that the newly reconciled could share in the liturgies of the Triduum. With Lent clearly a season focused on Baptism, Penance found a home there as well.

The Order of Penitents were people that had fallen into serious sin after Baptism – they would confess to the bishop, and then do penance for a period of time – and would be known by the clothes they wore, by being sent from Mass after the readings, etc. So, there was a Baptismal sense to this originally – and ashes were a sing of penance.

In the middle ages the Catechumenate disappeared from the church's life and eventually the Order of Penitents with it. The tie to a Baptismal sense faded, but the penance part of Lent continued and was emphasized. Repentance was seen more in the light of escaping the punishment of sin than a renewal of Baptismal promises. The significance of the ashes changed also.

Ashes as A reminder of Mortality "Remember man that thou art dust and unto dust thou shalt return."
The sense of mortality was emphasized to help encourage people to seriously consider their sins and make a firm amendment to change.

The Second Vatican Council
The 2nd Vatican Council restored the Catechumenate and with it a Baptismal focus. Since Ash Wednesday marks the beginning of Lent, it is a natural spot to mark the beginning of a Baptismal focus – and this is reflected in the new formula – Turn away from sin and be faithful to the Gospel. Or, Repent and hear the Good News. These formulations show a very pointed Baptismal focus as that is the whole idea behind becoming a Christian.

Symbol of Ownership.
In the Bible a mark on the forehead is a symbol of a person's ownership. By having our foreheads marked with the sign of a cross, we proclaim that we belong to Jesus Christ, who died on a Cross.
This is in imitation of the spiritual mark or seal that is put on a Christian in baptism, when he is delivered from slavery to sin and the devil and made a slave of righteousness and Christ (Rom. 6:3-18).

Ties to Revelation
"Then I looked, and lo, on Mount Zion stood the Lamb, and with him a hundred and forty-four thousand who had his name and his Father's name written on their foreheads." (Revelation 14:1)
This is in contrast to the followers of the beast, who have the number 666 on their foreheads or hands.
The reference to the sealing of the servants of God for their protection in Revelation is an allusion to a parallel passage in Ezekiel, where Ezekiel also sees a sealing of the servants of God for their protection:
"And the LORD said to him [one of the four cherubim], 'Go through the city, through Jerusalem, and put a mark [literally, "a tav"] upon the foreheads of the men who sigh and groan over all the abominations that are committed in it.' And to the others he said in my hearing, 'Pass through the city after him, and smite; your eye shall not spare, and you shall show no pity; slay old men outright, young men and maidens, little children and women, but touch no one upon whom is the mark. And begin at my sanctuary.' So they began with the elders who were before the house." (Ezekiel 9:4-6)

X Marks the Spot The Greek symbol for X is called Chi, and Chi is the first letter in Christos or Christ.
The early Church Fathers seized on this tav-chi-cross-christos connection and expounded it in their homilies, seeing in Ezekiel a prophetic foreshadowing of the sealing of Christians as servants of Christ. It is also part of the background to the Catholic practice of making the sign of the cross, which in the early centuries (as can be documented from the second century on) was practiced by using one's thumb to furrow one's brow with a small sign of the cross, like Catholics do today at the reading of the Gospel during Mass. And so, we are marked with Christ, in the form of an X which is also the crucifix and which shows we belong to Christ.