Since ancient times, tribes across the Zagros Mountains and in Mesopotamia have celebrated the first night of Winter. For Kurds, the night has held sacred meanings that are tied together with the various beliefs that ancient tribes once held and that some hold to this day. The night, which usually falls on December 21, is the longest night of the year better known as the Winter Solistice, when the sun is at its greatest distance opposite the equatorial plane relative a polar hemisphere.

The Night of Winter, which in Kurdish is Seva Zistanê or Sewî Zistan (also, Sewî Zimsan) is an unofficial holiday celebrated by communities throughout the Kurdistan region in the Middle East. The night is regarded as one of the oldest holidays still observed by modern Kurds and was celebrated by ancient tribes in the region as a holy day.

Since the night is the longest in the year, the belief is that the night signifies a period where darkness is making an attempt to defeat good. Following this long night, the days begin to turn longer.