The longest night of the year in the past 50 years

Yalda is the beginning of winter and the last night of autumn, and it is the longest night of the year”. In the first century, significant numbers of Eastern Christians were settled in Parthian and Sasanian territories, where they had received protection from religious persecution. Through them, Iranians (i.e. Parthians, Persians etc.) came in contact with Christian religious observances, including, it seems, Nestorian Christian Yalda, which in Syriac (a Middle Aramaic dialect) literally means “birth” but in a religious context was also the Syriac Christian proper name for Christmas,[rs 6][rs 4][rs 1][rs 3] and which—because it fell nine months after Annunciation—was celebrated on eve of the winter solstice. The Christian festival’s name passed to the non-Christian neighbors and although it is not clear when and where the Syriac term was borrowed into Persian, gradually ‘Shab-e Yalda’ and ‘Shab-e Chelleh’ became synonymous and the two are used interchangeably.