(While thinking long & hard about the Black Cauldron movie) In Fact, the whole plot resembles The Legend of Zelda.

1. Taron=Link
2. Eilonwy=Zelda
3. Horned King=Ganon
4. Cauldron Born=Stalfos 
5. Gurgi=Navi
6. Prydain=Hyrule

Need I go on? Wait a minute...I gotta think outside the box, which comes first, the chicken or the egg, this was released in 1985. & Legend of Zelda? In 1986. You gotta wonder if Shigeru Miyamoto got inspiration from the Black Cauldron while working on the Legend of Zelda, this could be a parody.

dont you mean ocarina of time? that sounds far more plausible because there was no navi in the first zelda game (not that I remember)

 

nonetheless to the theory Cave!

 

i know the book that the disney film is based off of came out in the 60's and the first zelda came out in the 80's if that means anything.

I think I have seen that movie.. Just about to guess the name..

Here's where your comparisons are off:

The books are about Taran growing from boy to man, gaining maturity as the series progresses. Link's journey in OOT does also take him from boy to man, but only in the literal sense. Zelda sends him back to the past at the end because Link is still mentally a boy.

Zelda and Eilonwy are arguably the most similar, at least with OOT involved. Eilonwy is an impulsive princess, always opting to act and never taking any of Taran's crap. Zelda acts immediately on Ganondorf's possible treachery when we first see her. The biggest difference is that Eilonwy is always opting to fight, while Zelda tends to take a background role when Link gets involved.

 

The Horned King and Ganon could not be more different. The Horned King in the movie is a combination of the main antagonist Arawn Death-Lord and the character of the Horned King, who only appeared in the first book. The Horned King is not much of a warrior in the movie, opting to take Arawn's sorcerer-in-the-shadows role. Ganon is more of a warrior/sorcerer hybrid.

 

The Cauldronborn and Stalfos are way too different. Stalfos are formerly people who got lost in the Lost Woods. Cauldronborn are former dead brought back to an undying state by means of the Black Cauldron.

Gurgi and Navi are nothing alike, movie or otherwise. Gurgi is Taran's companion, a beastly figure in the books. Gurgi is not intelligent, being bribed along in the first journey by food. Navi, while Link's companion, is a tiny fairy, following Link to guide him.

 

And in your comparison, where does Fflewddur Fflam fit in? What about Creeper, the character invented for the movie? Doli, Dallben and Hen-Wen? Orddu, Orwen and Orgoch? And what would the Black Cauldron be in your Your comparison doesn't totally fit, and this isn't even counting characters that only appear in the books.

 

The Chronicles of Prydain, to my knowledge, were never part of LoZ's inspiration, much less Disney's adaptation.

Now that I think about it; I think I could add one more comparisons, but don't be too hard on me, because this a tad rushed.

• Dalben: Link's Uncle/ The Great Deku Tree