6 YEARS AFTER…
Hans Zimmer has apparently been sued by the Holst foundation and music publishers ‘J. Curwen & Sons’. They claim elements of Zimmer’s Gladiator (in fact, a motif used in ‘The Battle’) borrow directly from Gustav Holsts ‘The Planets’, namely ‘Mars: Bringer of War’. Zimmer and his lawyers of course refute this, though the composer has likened parts of his score to Holst’s masterpiece, in terms of its musical language, in the past. (…)

Pure greed from people who had nothing to do with the music anyway. Copyright is way too long. 70 years after someone's death so that their grandchildren can harvest profits… it's too much.
Anyway Hans could probably sue half the people writing film music these days since 90% of scores sound like they've been stolen from his repertoire.
Who's to say it was even Zimmer's idea? Ridley Scott is a bit of an infamous auteur/control freak. It wouldn't surprise me one bit if he just temp tracked the scene with Holst and insisted Zimmer stick to it.
Star Wars did the exact same thing (with the same suite no less) and sounds just as close, but you don't see anyone demanding John Williams pay up for it.