Ouroboros

The wedding ring originated in Babylon, the cradle of civilization. The most ancient ring discovered there is in the shape of the eternal serpent.
The ouroboros has several meanings interwoven into it. Foremost is the symbolism of the serpent biting, devouring, eating its own tail. This symbolises the cyclic Nature of the Universe: creation out of destruction, Life out of Death. The ouroboros eats its own tail to sustain its life, in an eternal cycle of renewal.
The Ouroboros often represents self-reflexivity or cyclicality, especially in the sense of something constantly re-creating itself, the eternal return, and other things perceived as cycles that begin anew as soon as they end. It can also represent the idea of primordial unity related to something existing in or persisting before any beginning with such force or qualities it cannot be extinguished.