yalda festivale di luce persiana - Persia Mirabile

In Zoroastrian tradition the longest and darkest night of the year was a particularly inauspicious day, and the practices of what is now known as "Shab-e Chelleh/Yalda" were originally customs intended to protect people from evil (see dews) during that long night,[rs 7] at which time the evil forces of Ahriman were imagined to be at their peak.