The Norns are three female divine beings who have more influence over the course of destiny than any other beings in the cosmos. They are the Norse counterparts of the Moirai, also known as the Sisters of Fate in Greek mythology.
They dwell within the Well of Urd beneath Yggdrasil, the great ash tree that stands at the center of the universe and holds the Nine Worlds in its branches and roots. They shape destiny by carving runes into the trunk of the tree, or, in some sagas and poems, by weaving destiny like a web or tapestry.
Their names are Urd ("What Once Was"), Verdandi (“What Is Coming into Being”) and Skuld (“What Shall Be”). A common misconception is that they correspond to the past, present, and future in a linear conception of time. A more sensitive analysis shows that they correspond instead to past, present, and necessity in a cyclical conception of time, as is discussed here.
Another common misconception is that the destiny woven or carved by the Norns is final and unalterable, as in the Greek concept of fate. The Norse/Germanic model of destiny, however, is far more dynamic and volatile than this, and leaves ample room for individual agency in the shaping of destiny.