This is one of those entries where it feels a bit redundant to write anything due to the sheer level of fannish devotion the show engenders. Particularly when I've not seen any of it.
Saint Seiya is the creation of Masami Kurumada. The original manga ran in the pages of Shonen Jump from '86 to '90, with the anime adaptation running '86 to '89.
So what's it about? My understanding is that involves young men in magic armour, acting as champions of Athena, battling other champions of other gods. With a lot of blood and violence.
It was a hit in France in the eighties, under the name Knights of the Zodiac. This would become it's Western name for all intents and purposes. It was this title that DiC and ADV used when they licensed it. The US release is a messy one, the show flopping on the Cartoon Network, where it was heavily censored despite being on at 1230am. And the ADV uncut release stalled after 60 episodes, when Toei refused to license any more episodes to them, meaning the release ended mid-arc.
Of course, a 17 year old shonen show is going to be a hard sell, even if it does have a hardcore of fans behind it. Had it been released earlier, like it's imitator Ronin Warriors, it probably would have stood a better chance, and have at least become one of those shows that have a cool cachet about them despite never having been a huge hit at the time.