The Norns are named Urd, Verdandi and Skuld ('that which was', 'that which is becoming' and 'what will be'). They place a rooster atop Yggdrasil every morning to wake the gods with it’s crowing.
Nothing happens in the cosmos that the Norns do not weave into the web of existence though they are never likely to change the fate of a person once it is woven, even with prayer and sacrifice.
It is said that at everyone’s birth a Norn is present and traditionally the mother was fed 'Norn Pudding.' This food was also made as an offering to the Norns to gain their favor at the birth.