Western Christian churches today mark Ash Wednesday, the start of Lent, the traditional 40-day period of fasting, prayer and penitence before Easter.
To observe the day, Roman Catholics, Episcopalians and Lutherans hold services during which the foreheads of the faithful are marked with the sign of the cross with ashes made from last year's Palm Sunday palms as a sign of repentence and reminder of mortality.
A clergy person or, in some cases, a lay person, applies the ashes with variations of the phrase: "Remember you are dust and unto dust you shall return."
The 40 days of Lent do not include Sundays. Easter falls on April 12 this year.
The fasting associated with Lent spawned pre-Lenten celebrations such as Mardi Gras (Fat Tuesday) and Carnivale as a last chance to eat, drink and be merry before the 40 days of self denial began.
Tradition holds that a Philadelphia staple -- the soft pretzel -- was created by a monk as a Lenten food at a time when the faithful abstained from meat and animal products, such as milk and eggs.
The Eastern Orthodox Church, which follows a different calendar, will mark the start of the Great Lent on what is called Clean Monday on March 2. Orthodox Easter is April 19.