Yalda (Persian: یلدا) , Yalda Night / Shab-e Yald� (Persian: شب یلدا), or Shab-e Chelleh (Persian: شب چله, Azerbaijani: �illa gecəsi)

is the Persian Winter Solstice Celebration^[1][2] which has been popular since ancient times. Yalda is celebrated on the Northern Hemisphere �s longest night of the year, that is, on the eve of the Winter Solstice. Depending on the shift of the calendar, Yalda is celebrated on or around December 20 or 21 each year.

Yalda has a history as long as the Mithraism religion. The Mithraists believed that this night is the night of the birth of Mithra, Persian god of light and truth. At the morning of the longest night of the year the Mithra was born.

Following the fall of the Sassanid Empire and the subsequent rise of Islam in Persia/Iran, the religious significance of the event was lost, and like other Zoroastrian festivals, Yalda became a social occasion when family and close friends would get together. Nonetheless, the obligatory serving of fresh fruit during mid-winter is reminiscent of the ancient customs of invoking the divinities to request protection of the winter crop.

The 13th century Persian poet Sa �di wrote in his Bustan: "The true morning will not come, until the Yalda Night is gone".

Following the Persian calendar reform of 1925, which pegged some seasonal events to specific days of the calendar, Yalda came to be celebrated on the night before and including the first day of the tenth month (Dey). Subject to seasonal drift, this day may sometimes fall a day before or a day after the actual Winter Solstice.

Yalda Night has been officially added to Iran �s List of National Treasures in a special ceremony in 2008

Yalda Tradition

In Zoroastrian tradition, the winter solstice with the longest night of the year was an auspicious day, and included customs intended to protect people from misfortune. On that day, people were advised to stay awake most of the night. They have small parties and gatherings and eat the last remaining fresh fruits from summer.

In modern days, although Yalda is not official holiday in Iran, families continue to hold traditional gatherings. Iranian radio and television offer special programmes on Yalda.

Watermelons are placed on the korsi, a traditional piece of furniture similar to a very short table, around which the family sit on the ground. On it, a blanket made of wool filling is thrown. People put their legs under the blanket. Inside the korsi, heat is generated by means of coal, electricity or gas heaters. Pomegranates are traditionally eaten on this night.

text is from Wikipedia