It was one of the first true anime I had watched when I was a kid.

Saint Seiya series are based on Greek mythology, but the stories take place in our current time. It is basically about wars between gods, and the human warriors who serve each of them. Some of the Greek gods tried to take over our world in our present time.

The two earlier series were Saint Seiya and Saint Seiya Hades.

The latest series now goes back in time to the last Holy War over 200 years ago when the last generation of Gold Saints fighting against Hades' army. The two only survivors were present in the first two series, yep both lived for over 200 years thanks to the gift from Athena.
I always like the Gold Saints the most over the actual main characters. The main characters are bronze saints who are in fact the lowest rank of warriors under Athena, who are supposed to be the weakest but the plot is always on the side of the main characters.

In the latest new series, it is mostly about Gold Saints fight against the enemies... as it should be. You send in your most powerful warriors, instead of some low rank ones.

I thought it was funny when Cancer Gold Saint of the last generation was in fact one of the strongest (the one in our current time was one of the weakest), the dude effortlessly defeated a powerful enemy sent by Hades (the god of underworld or death) on their own turf...the entrance to the underworld (yep, he could teleport himself to the world of death and come back), then as two of the gods who work for Hades were playing a chess game, the Cancer Gold Saint opened a portal in this world as he teleporting back from the world of dead, right appeared a few meters above the chess board. As he fell down and dropped onto the table, the chess board was smashed as he stood on the table between the two gods. Then he took a good look at both gods, "wow, you two are really twins, which one is... ". So arrogant haha...