Among all peoples of the world, the most common times for celebration are the Winter Solstice and the Vernal Equinox. Considering that the austerity and bleakness of Winter (in contrast to the relative abundance and warmth of Summer) would be so impactful upon the lives of primitive peoples living in temperate climates these festival times -- and even Sun-worship -- should come as no surprise. Stonehenge and hundreds of other megalithic structures throughout the world were constructed to receive a shaft of sunlight in their central chamber at solstice dawn.
December feasts were common in Europe because it was necessary to slaughter cattle that could not be fed during the winter and because the meat could be preserved by the cold weather. The word Yule may come from the Anglo-Saxon word geol (feast), applied to December (geola, feast month). Or it may come from a Norse-Saxon word meaning wheel, referring to the seasonal cycles of the sun. Or it could have come from the Scandinavian Jule (Jul), who was the god of sex and fertility. ("Tide" as in "yuletide" may have come from an Old English word meaning time, occasion or season.)
Midwinter sun festivals were celebrated in ancient Britain & Scandinavia. In Germanic & Scandinavian countries a huge log was carried into the house to serve as the foundation for holiday fires. The Yule log at Jultid (Yuletide) would burn for twelve days, and a different sacrifice would be made on each of the twelve days. Lighted candles and winter fires were used by sun-worshippers to encourage the rebirth of the Sun. Similarly tying fruit to the branches of trees was intended to encourage the coming of Spring.
In the Northern Hemisphere, the Winter Solstice occurs around December 21st, when the Sun is at its greatest distance below the celestial equator. The Vernal Equinox occurs around March 21st when the sun crosses the celestial equator and days have the same duration as nights ("equinox" comes from a Latin word meaning "time of equal days and nights"). The Vernal Equinox marks the beginning of Spring. The constellation (Zodiac sign) visible at dawn on the day of the Vernal Equinox has been regarded as of special significance (currently changing from Pisces to Aquarius due to the 26,000 year precession of the Earth -- the advent of "the Age of Aquarius").
The chief holiday for the ancient Hebrews was celebrated at the first full moon after the Vernal Equinox. Although this holiday was originally a celebration of Spring, it was later celebrated in remembrance of the Exodus from Egypt and was called Passover. The holiday entered Christian celebration by the fact that Christ was reputedly arrested and crucified at Passover. Because Christians insisted that Easter should be celebrated on a Sunday, the Council of Nicea decreed that Easter be the first Sunday after the fourteenth day of the moon (which is approximately the full moon) following the date of the Vernal Equinox (which is assumed to be March 21st). In the first centuries of Christianity Easter was by far the most significant Christian holiday (holy day) and Christmas was not a holiday at all.
The word for "Easter" in most of the Romance Languages is a variant of the Hebrew "Passover", but the English word is unrelated to these forms. Possibly, the English word "Easter" is derived from the name of an Anglo-Saxon goddess of Spring, "Eostre". Or it may have come from "Ishtar/Astarte" the Babylonian/Chaldean Venus who was the consort of the sun-god. Or it may have come from the same root as "east", associating the source of the rising sun with the resurrection ("rising") of Christ. Sunrise service, painted eggs and rabbits have all symbolized rebirth and fertility in Spring celebrations from ancient times. Celebration of motherhood (mother's day) is also most often in the Spring, another possible association with fertility.
