In Western jewelry, the infinity-symbol-shaped bow or knot has symbolized endless love and constancy as far back as 500AD, when it was employed in Celtic rings. The sentimental Victorians loved the bow as a tidy metaphor for undying affection: it loops around itself in an eternal twist, forever and ever, never beginning and never ending. In a time when lovers were often parted for long periods, it could be a comforting metaphor for intimacy despite being apart. Think about what would happen if you pulled both ends of this bow: the further the distance, the tighter the knot.
The further the distance, the tighter the knot.
The knot also loops around on itself and travels in an eternal twist, for the love between the couple is forever undying. Put all these together and you have a rather special and beautiful symbol, one that encompasses much of the basis of what sentimental jewels are created for. - See more at: http://artofmourning.com/2011/01/02/symbolism-sunday-the-knot/#sthash.mK6u3V48.dpuf