Iranians around the world celebrate Yalda, which is one of the most ancient Persian festivals. The festival dates back to the time when a majority of Persians were followers of Zoroastrianism prior to the advent of Islam. On Yalda festival, Iranians celebrate the arrival of winter, the renewal of the sun and the victory of light over darkness. Considered the longest night of the year, Yalda eve is the night when ancient Iranians celebrated the birth of Mithra, the goddess of light. One of the themes of the festival was the temporary subversion of order. Masters and servants reversed roles. The king dressed in white would change place with ordinary people. A mock king was crowned and masquerades spilled into the streets. As the old year died, rules of ordinary living were relaxed. This tradition persisted till Sassanian period, and is mentioned by Biruni and others in their recordings of pre-Islamic rituals and festivals. Its’ origin goes back to the Babylonian New Year celebration. These people believed the first creation was order that came out of chaos. To appreciate and celebrate the first creation they had a festival and all roles were reversed. Disorder and chaos ruled for a day and eventually order was restored and succeeded at the end of the festival.