I've done a little digging around and I think I might have something that conveys a similar meaning. Perhaps someone will be so kind to let me know if this makes sense:

einn mega er einga

--- In norse_course@yahoogroups.com, "servupro" <servupro@...> wrote:
>
> I'm trying to get a short phrase translated from modern English to Old Norse (I guess old West Norse?) but I'm no linguist and its just one short phrase so I was hoping I might find someone here who can help me. The phrase is "there can be only one".
>
> Is there anyone out there who can help me?
>
> Thank you in advance for your reply! ;-)
>
> Mark
>