This is a sort of fairy tale story.  It starts off with Merlin being very young, born when the last version of him died, with Vivian being a young girl.  They grow up together, become lovers, and eventually Merlin (who's growing up obscenely fast) dies with Vivian still young, only to be born again and meet the next Vivian. It's very well written, although bizarre.

Dates:
Merlin's Bones: 1995