A little history of Ash Wednesday.

Ashes are an ancient symbol of penance predating Christianity. They remind us of our mortality. We come from dust and unto dust we shall return.

They are made from the burned palms of last year. Placing ashes on the head was an ancient penitential custom, as is evident in the Bible (e.g. Jonas 3:5-9)

From about the fifth century, sinners confessed their sins on Ash Wednesday. They did not receive absolution but were enrolled in the "order of penitents," signified by placing ashes in the form of a cross on their foreheads. They were then assigned public penance to be performed throughout Lent and on Holy Thursday morning they received absolution.

2005 Lenten Booklet