The word comes from shrive, which means “to confess”. During Lent Christians are supposed to perform some kind of penance, usually food deprivation, so fatty foods would be gorged upon beforehand. The word carnival comes from came levare referring to abstaining from meat. Meat, dairy and eggs were luxury foods to be given up for the forty days of Lent. As these foods were also perishables they needed to be used up, so pancakes and other similar treats would be made.
In England the day would be celebrated by raucous football games, until the 1835 Highway Act banned the playing of football in public thoroughfares. These days the festivities are limited to pancake races, whereby the runners must toss a pancake in a frying pan as they run.
The word Lent probably derives from the Anglo-Saxon word lencten which roughly translates as lengthening and refers to the longer spring days. It is thought that it was originally a Pagan festival to mourn the death of Tammuz, a Babylonian deity. The story goes that he was killed by a wild boar whilst hunting. His parents mourned for forty days after which Tammuz was restored to life. So it is likely that in pre-Christian times there would be festivals celebrating the re-birth of the land at springtime.
Similarly in Eastern Slavic nations, such as Russia, Pagan festivals celebrating the end of winter were appropriated by the Eastern Orthodox Church. Known as Maslenitsa, there is a week of festivities before Lent. It is also known as Butter Week as dairy products are used up to make pancakes, or Blintz. Blintz is a Yiddish word derived from the Russian blinyet meaning little pancake; there is a yummy recipe here.
There would also be a general letting-down of hair with sleigh rides, snowball fights and family visits. During the Soviet era this religious festival was banned, but is now celebrated again by Eastern Orthodox followers.
In pre-Christian times the festival celebrated the fertility goddess, Kostroma. A straw effigy of Kostroma would be created and then burned, in scenes no doubt familiar to fans of the film “The Wicker Man” starring Edward Woodward.