Easter is the oldest and most important Christian festival, marking the end of the fasting season of Lent and the death, on Good (derived from God's) Friday and resurrection of Jesus Christ, on Easter Sunday. It has deeper and more complex associations than Christmas, particularly in the Orthodox Christian world.

There are many customs and traditions associated with Easter which, like most other holiday and feast days, are derived from a combination of both Jewish lore and pre-Christian and pagan practices. It is named after Eostre, the goddess of fertility and birth, worshipped by first-century pagans at the vernal equinox. Christian missionaries saw this celebration took place around the time of the resurrection of Christ, so they adopted Easter as a Christian holiday to increase conversion.

Why does the date move around so much?

Discussion of the dating of Easter has been the subject of intense debate among the Christian churches since the second century AD. For many years it has been agreed that Easter falls on the first Sunday after the full moon that occurs on or after the Vernal (spring) Equinox (21 March). If the full moon falls on a Sunday then Easter is the next Sunday. This means that Easter can fall as early as 22 March or as late as 25 April. Next year it falls on 23 March, the second-earliest date possible. Easter last fell on the latest possible date, 25 April in 1943, and will next fall on that date in 2038. It is the origin of the phrase "moveable feast".

What is the link with Passover?

Some of the early Christian debate centred over the desire to keep the date of Easter separate from the week-long Jewish festival of Passover, which celebrates the Exodus and freedom of the Israelites from ancient Egypt. It is believed that the Last Supper was in reality the Seder meal, which traditionally marks the start of Passover. The word Paschal, used to describe many things associated with Easter, itself derives from Pascha, the Greek/Latin transliteration of Pesach, the Hebrew word for Passover.

So what is the Paschal Lamb?

Lamb has become associated with Easter for two reasons: one is that Christ became known as the Lamb of God in Christian theology, atoning for the sins of man by his sacrifice on the cross. But the idea of the "sacrificial lamb" is older. Pesach means "skipping" or "passing over" and, according to Jewish lore, the Israelites marked their doors with the blood of a lamb to prevent the Angel of Death killing their first born; their doors were therefore literally "passed over". Jewish temples began to sacrifice lambs ritually to mark the Passover.

But the fact that newborn lambs mature into something that can be eaten around Easter must also be taken into account.

Why have rabbits and eggs become linked with Easter?

Eggs, of course, are ancient symbols of fertility, for very obvious reasons, while the Seder meal incorporates a hard boiled egg as a symbol of new life. The ancient Persians also painted eggs for Nowrooz, their new-year celebration falling on the spring equinox. An egg has also been seen to be associated with the rebirth or resurrection of Christ. The custom of eating them also derives from the fact that they were forbidden during Lent.

There are a great many rituals associated with eggs, mainly dating from medieval times in Europe, usually involving decorating, throwing, rolling or hiding eggs for children to find them. The Easter bunny or rabbit comes from the hare, another ancient, pre-Christian symbol of fertility associated with spring. But it gets even more complicated than that. Anglo-Saxon mythology says Eostara changed her pet bird into a rabbit to entertain a group of children, and the rabbit laid brightly-coloured eggs for them. The chocolate bunny, like the chocolate Easter egg, is a more recent idea, stemming from 18th- and 19th-century middle-European confectionery traditions.

What other foods are associated with Easter?

A great many. The Finns and Swedish eat mammi or memma, a baked malt porridge, while in Naples they eat pastiera, a cake made from ricotta cheese, and in the province of Salamanca, a meat pie called hornazo, made from pork loin, chorizo sausage and hard boiled eggs. The Greeks eat a soup made from lambs' innards, magritsa, on Easter Sunday. Ham tends to be more popular in the United States, where the custom was brought by Scandinavians and eastern Europeans.

There are many Easter baking traditions which range from simnel cake, a light fruit cake made in Britain, to kulich, a traditional bread in Russia and the Ukraine, while Poland's mazurki are sweet cakes made with honey and filled with nuts and fruit. Hot cross buns, made around Europe, are the most well known, carrying the symbol of the cross and containing no ingredients that contravened the Lenten tradition.

The idea of eating fish on Good Friday (and all Fridays) comes from the early Christians who decreed that Friday would be a fast day on which no meat was eaten because that was the day Christ was crucified.

And other Easter customs?

Where do you start? Many stem from ancient folklore and are specific to certain areas, usually reflecting the desire among people to get out and about on the first holiday of spring and the end of a fasting period. That's why we get Easter parades, Easter bonnets, egg-rolling festivals and so on. But surely the oddest custom used to take place in the Czech Republic, Hungary and Slovakia, where there was a tradition of spanking or whipping of women on Easter Monday. In the morning, males throw water at females and spank them with a special handmade whip, consisting of eight, 12 or even 24 withies (willow rods), which is usually from half a metre to two metres long and decorated with coloured ribbons at the end. The spanking is symbolic and normally not painful or intended to cause suffering.

A legend says females should be spanked in order to keep their health and beauty during the next year.