The foundation of the Christian religion is the events that happened at Mount Calvary 2 millennia ago. Jesus's death by crucifixion, subsequent resurrection and ascendancy to Heaven are foundations upon which the Christian religion is built.
Illustration 1: A depiction of goddess Ostara (Eostre).
Consequently the most important holiday in the Christian calendar is the Easter holiday. Easter Sunday marks the day on which Jesus resurrected. That resurrection is the basis of all Christian theology.
Some people like to think Christmas is the most important but it is simply the most commercialised.
There are many calendars in this world, the Chinese have their own calendar defining such things as year of the dog, year of the chicken and so on. This year 2013 is year 4711 in the Chinese calendar and is the year of the rabbit.
The Buddhists have their own calendar based on the nirvana of Buddha. This year (2013) is 2557 in the Buddhist calendar.
However dates as we know them today are based on the Christian calendar, or to be more precise the Catholic calendar, known as the Gregorian Calendar.
Many people might not know, but Easter is also closely related to sun worship and the worship of pagan gods.
Easter is held on the first Sunday after the first full moon of the spring equinox in the Northern hemisphere. The problem was that Easter day tended to drift over the years because the solar cycle (year) is not a whole number multiple of the Earth's rotational cycle (day). As a result civil calendars based on merely counting the number of days tend to drift relative to the solar year.
In 1582 Pope Gregory signed a degree describing an elaborate formula to calculate the date of Easter based on the solar cycle and not on the then widely used civil calendar the Julian Calendar. The resulting calendar, the Gregorian Calendar, is the calendar that is today most widely used as the civil calendar in the world. This year is numbered 2013AD based on the Gregorian calendar. It is the number of the year based on the Catholic formula for calculating the days of Easter.
Other ancient Christian denominations such as the Eastern Orthodox, the Greek Orthodoc, the Coptic and the Ethiopian Orthodox churches have their own year numbers and celebrate Easter on different days to the Catholic based Christians.
The feast of Easter itself is not entirely based on the resurrection of Jesus but was adopted by Christians from pre-existing pagan religions. As alluded to earlier the feast is related to the first full moon after the spring equinox. The equinox is the day of the year when the sun is exactly above the equator and day is equal to night at every latitude in the world. There are two equinoxes one just before spring and summer, the other before autumn and winter. Easter is celebrated after the first full moon of the spring equinox and is related to the most ancient practices of worshipping the sun and the moon.
However even though it is related to sun worship, Easter was not passed on to Christians directly from sun worshippers. The name Easter is not mentioned anywhere in the Bible but is derived from the Eastre the name of the Anglo-Saxon goddess of spring.
The Anglo-Saxons themselves are thought to have adopted the name from Eostre or Austro the Barbarian goddess of dawn. Notice the pagan goddesses are associated with the times of spring or dawn, largely considered by humans to be times of renewal, awakening or resurrection.
Illustration 2: A depiction of Ishtar goddess of fertility, love and sex found on a Babylonian vase kept in a French museu
In Middle East, the ancient Babylonians, whose civilisation existed about 2000 years before Christ, held summer festives linked to the god Tammuz who was brought back (resurrected) from the Underworld every six months. Tammuz had been send to the underworld by Ishtar, the goddess of fertility, love and sex.
The Babylonian legend has it that Ishtar demanded of her sister who was ruler of the underworld that she be let into the underworld. Her sister agreed but with the condition that at each gate to the underworld she shed an item of clothing. Ishtar agreed and proceeded to enter the underworld. At the seventh gate (seven?!) she was completely naked. Despite that she was now naked, Ishtar proceeded to sit on the throne of the underworld whereupon the other gods of the underworld gazed upon her with the eyes of death. She became a corpse and was hung on a nail.
However a servant of the gods Enki pleaded with the gods and Ishtar was resurrected. She was allowed to go back but she had to find someone to replace her. When Ishtar came back from the underworld she found that her lover Tammuz was not mourning her at all. So she send him to the Underworld. Tammuz's sister Geshtinanna was sad and volunteered to spend six months of the year in the Underworld on his behalf. Consequently Tammuz came back from the Underworld every six months and his coming (resurrection) was marked by a festival.
For Christians Easter marks the death and resurrection of Jesus Christ but as we can see the whole idea of death and resurrection of a god or gods had existed beforehand.
Also, nowhere in the Bible are hares and eggs mentioned but today the Easter bunny and the Easter egg are considered contemporary items of the culture surrounding the Easter festival. Where did they come from?
The Easter bunny and East egg have their origins in ancient Barbarian fertility lore. The hare is a symbol of copious breeding and copulation while eggs are symbols of fertility. As mentioned earlier the Babylonian goddess Ishtar was the goddess of among other things sex, love and fertility.
Again as mentioned earlier the name Easter comes directly from Eastre an Anglo-Saxon goddess who - to quote from French scholars Alfred Ernout and Antionne Meillet - “represented spring fecundity, love and carnal pleasure that leads to fecundity.”
In short the contemporary symbols of Easter are directly associated with Barbarian (ancient European) beliefs on fertility, love and sex and the Babylonian goddess of the same.
In fact the followers of Ishtar engaged in what is called sacred prostitution. The requirement was that at least once in their lifetime a follower had to go to the temple and engage in public sex with a complete stranger.
Spring is the time of year when flora blossoms and fauna procreates in abundance and the world renews itself, and ancient humans have made it the time to celebrate renewal. Spring is marked by the time when the sun 'comes back' and days become longer than nights.
The Gregorian Calendar is explicitly defined such that the date of Easter never drifts with respect to the time when the sun 'comes back' in Northern hemisphere terms. The pre-summer (Northern hemispheric) equinox occurs on 21 March each year as defined by the Gregorian Calendar. Leap years, and number of days in months are so carefully defined that the day when sun comes back never ever shifts in the Gregorian Calendar.
Easter Sunday is then set as the first Sunday after the first full moon after the equinox heralding summer. In other words Jesus's resurrection is made to follow the cycles of the sun and the moon. Also, the festival itself is associated with various gods of fertility, love and sex.
The Gregorian Calendar was decreed by Pope Gregory so it is the Catholic church which calculates the dates of Easter for most of the world.
The Protestant and Pentecostal variations of Christianity mostly branched off from Catholicism and use the same date for Easter though I doubt whether most of their pastors and ministers would be able to explain how this date is defined. The process of calculating the date of Easter, called Computus, which had been the subject of much controversy was thus put to rest by Pope Gregory. The name Computus is what eventually gave rise to the English words computation and computer.
Let me make it clear, I am not claiming that Christians worship the sun, the moon and pagan gods. However, I consider it better to open my eyes and seek knowledge than to keep my eyes shut and be led to nowhere. This is not a pun for the Christian practice of praying with the eyes shut either.
However it is clear that their religious practices have borrowed from past religions to a much greater extend than some would admit.
Note that an informed look at the evolution of the Easter holidays, they holiest days in the Christian calendar, does not tally with the creationist view of the world. Like everything in the world, the Christian religion itself is a product of evolution.