Ashes and the Forty Days of Lent 

Ashes are an ancient sign of penitence; from the middle ages it became the custom to begin Lent by being marked in ash with the sign of the cross. This practice gives the name to Ash Wednesday and marks the beginning of Lent.

Originally this season was a time for candidates for baptism to be instructed in Christian faith, and for penitents and those excommunicated prepared themselves, through fasting and penance, to be readmitted to communion. Over time, the whole Christian community was invited to join them in the process of study and repentance over forty days,  reminding them of the forty days that Jesus spent in the wilderness, being tested by Satan.

The exact calculation of the forty days has varied over Christian history. It is now usual in the West to count them continuously to the end of Holy Week (not including Sundays), so beginning Lent on the sixth Wednesday before Easter, Ash Wednesday.

As Holy Week approaches, the season darkens as the readings begin to anticipate the story of Christ’s suffering and death. Passiontide begins on the Fifth Sunday of Lent and Holy Week begins on Palm Sunday. Through participation in the events leading up to his crucifixion, we share in Christ’s journey, from his triumphal entry into Jerusalem to the empty tomb on Easter morning. 

Above text adapted from Common Worship, Times & Seasons