Lent is the forty day period before Easter, excluding Sundays, which begins on Ash Wednesday and ends on Holy Saturday (the day before Easter Sunday). [This traditional ennumeration does not precisely coincide with the calendar according to the liturgical reform. In order to give special prominence to the Sacred Triduum (Mass of the Lord's Supper, Good Friday, Easter Vigil) the current calendar counts Lent as only from Ash Wednesday to Holy Thursday, up to the Mass of the Lord's Supper. Even so, Lenten practices are properly maintained up to the Easter Vigil, excluding Sundays, as before.]
History of Lent
Since the earliest times of the Church, there is evidence of some kind of Lenten preparation for Easter. Lent becomes more regularized after the legalization of Christianity in A.D. 313. The Council of Nicea (325), in its disciplinary canons, noted that two provincial synods should be held each year, "one before the 40 days of Lent." Pope St. Leo (d. 461) preached that the faithful must "fulfill with their fasts the Apostolic institution of the 40 days," again noting the apostolic origins of Lent. One can safely conclude that by the end of the fourth century, the 40-day period of Easter preparation known as Lent existed, and that prayer and fasting constituted its primary spiritual exercises.
Of course, the number "40" has always had special spiritual significance regarding preparation. On Mount Sinai, preparing to receive the Ten Commandments, "Moses stayed there with the Lord for 40 days and 40 nights, without eating any food or drinking any water" (Ex 34:28). Elijah walked "40 days and 40 nights" to the mountain of the Lord, Mount Horeb (another name for Sinai) (I Kgs 19:8). Most importantly, Jesus fasted and prayed for "40 days and 40 nights" in the desert before He began His public ministry (Mt 4:2).
Once the 40 days of Lent were established, the next development concerned how much fasting was to be done. In Jerusalem, for instance, people fasted for 40 days, Monday through Friday, but not on Saturday or Sunday, thereby making Lent last for eight weeks. In Rome and in the West, people fasted for six weeks, Monday through Saturday, thereby making Lent last for six weeks. Eventually, the practice prevailed of fasting for six days a week over the course of six weeks, and Ash Wednesday was instituted to bring the number of fast days before Easter to 40. The rules of fasting varied. First, some areas of the Church abstained from all forms of meat and animal products, while others made exceptions for food like fish. For example, Pope St. Gregory (d. 604), writing to St. Augustine of Canterbury, issued the following rule: "We abstain from flesh, meat, and from all things that come from flesh, as milk, cheese and eggs."
Over the years, modifications have been made to the Lenten observances, making our practices not only simple but also easy. Ash Wednesday still marks the beginning of Lent, which lasts for 40 days, not including Sundays. The present fasting and abstinence laws are very simple: On Ash Wednesday and Good Friday, the faithful fast (having only one full meal a day and smaller snacks to keep up one's strength) and abstain from meat; on the other Fridays of Lent, the faithful abstain from meat. People are still encouraged "to give up something" for Lent as a sacrifice. (An interesting note is that technically on Sundays and solemnities like St. Joseph's Day (March 19) and the Annunciation (March 25), one is exempt and can partake of whatever has been offered up for Lent.