The origin of the custom of using ashes in religious rituals is lost in the midst of Pre-History. But we do find reference of the practice of our own religious traditions in both the Old and New Testaments.
Old Testamant:
Jer 6:26 - Put on a sackcloth and roll in ashes.
Is 58:5 - Declare a day of penance that a man bow his head like a reed and put on sackcloth and ashes.
Dan 9:3 - I turned to God with prayer, fasting, sackcloth, and ashes.
Jonah 3:6 - King of Ninevah
Judith 4:11 - They prostrated themselves in front of the temple with ashes strewn on their head.
1 Mac 3:47 - That day they fasted, wors sackcloth, thy sprinkled ashes on their heads.
New Testament:
Matt 11:21 - They wore sackcloth and ashes
In the early church - pen. before Baptism
960 - Roman - Germanic Pontifical
Ash Wednesday
Turn away from sin and be faithful to the Gospel.
Ash Wednesday calls us to conversion.
It's our time to look at our lives; to effect change and to be imitators of Christ.