Before that movie, it started charting on the top 1000 in 1971, after a TV movie version of
Tristan &
Isolde came out. There was also a
Salvador Dali book, and a recording of Wagner's opera. That first boost might be why it was used by the author of the 1979 book, that inspired the Legends of the Fall movie. It was cool enough for a character - but not ready to be used for real boys yet. Kinda like
Luna when the HP books were written?
I feel like
Tristan was inevitably going to be popular ... in part because as a youth in the 80s (having only seen it as the opera title) I found it appealing ... I think the things that delayed its popularity, were the similarity to
Kristen (which was taking off in 1970), the general unfamiliarity, & association with medieval romance (which I think would have made it seem too "flaky" to people then, kind of like using
Lancelot for a boy).
Those things were not going to inhibit parents anymore (people around my age, who probably were aware of it before the movie and liked it) at the time the Pitt portrayal came out, so it took right off. But, I think it might have done anyway - even without the movie, just to a lesser extent, or a bit later.
- mirfak