Urd is the first and eldest of the three Norns, the fate-goddesses who sit beneath the world-tree Yggdrasil and shape the destinies of gods and men. Her name, cognate with the old English wyrd, fate, means roughly that which became, and she keeps the past, as her sisters Verdandi and Skuld keep the present and the future.
Beneath the tree lies the Well of Urd (Urdarbrunnr), the most sacred of the wells at the roots of Yggdrasil, and Snorri tells that the Norns draw water from it each day and pour it, mixed with the clay of its banks, over the great ash to keep its branches from rotting, so that the tree of the world is sustained by the tending of fate itself. It is at the Well of Urd that the gods hold their daily council. As the norn of the past, Urd embodies all that has already been laid down and cannot be unmade, the accumulated weight of what has happened out of which the present and the future are drawn. The sources note that norns beyond the three also attend each birth, but Urd, who gives the well its name, stands foremost among them.