Indian society was divided into a caste system based on a person's

Most caste systems in our history were based on a person's skin color. I'm gonna take a guess that it would be the same for this part of the world.

Ancient history says that it's from Brahma's divine manifestation of four groups. Priests and teachers were cast from his mouth, rulers and warriors from his arms, merchants and traders from his thighs, and workers and peasants from his feet.

And now it's from their ancestors, previous wealth, deeds and stuff.