The story takes place in Japan around 1985.
The story of Saint Seiya
The story is about 5 orphan youngsters between 13 - 16 y/o who are the main characters of the story. They are the 5 bronze saints : Pegasus Seiya, Cygnus Hyoga, Andromeda Shun, Dragon Shiryu and Phoenix Ikki. They are given a home by the Kido Foundation led by Mitsumasa Kido. Each one of them is sent to a training ground all over the world to become a saint and bring back a sacred cloth so they can later compete in a Tournament (Galaxian War) to win the Sagitarius gold cloth. Mitsumasa Kido died so his granddaughter Saori Kido lead the tournament. But one of the 5 bronze saint from above robs the cloth and escape. The other four go on a mission to get the cloth back and find out who the other one is and why he betrayed them.
Later they find out that Saori the reincarnation is of the goddess Athena who comes back every 100 years to stop evil and that the Great Pope in Athena's sanctuary tried to kill her on the night of her birth, 13 years before their training.
The 5 bronze saints swear loyalty to the goddess and set on a battle against the Popes army of saints including some bronze, silver and gold saints. Once the Pope is defeated the 5 saints ( who now have silver cloths) fight against Polaris Hilda and her God Warriors in Asgard.
After that they fight against Poseidon the Sea God (who had controlled Hilda) and his 7 scale shoguns. This story and the Asgard sory only exist in the anime.
In the manga they also fight again Hades which is the final story.