Near the end of Tigana, Brendel gets all philosophical and tells Dianora about a story his nurse (I think) used to tell him when he was a boy, about a land called 'Finivar', which was the 'real' world, as opposed to where they were now. He then goes on to say that in his dreams, he pictures himself in Finivar, with her by his side, and there is nothing separating them anymore--and Dianora gets all weak in the knees because he is finally telling her he loves her. She (or he?) mentions Finivar once again just before he dies, saying she'll meet him there soon.

GGK said in interviews something along the lines of his beginning to conceptualize the world of Fionavar when he wrote Tigana, but it wasn't fully realized yet. In addition, the relationship between the Tiganese princes and the wizards (the latter's magic being controlled/bound by the former) was a foundation for the description of magic in Fionavar, in which wizards sources are living people 'bound' to them.

Like I said, obscure references.