Rg-Veda and Vedic religious tradition

Rg-Veda :
 

texts of the Vedas are claimed to have been revealed to sages of old, texts known as sruti, i.e.: that which is revealed, whereas later sacred texts receive secondary status as smriti, i.e. that which is heard (i.e.: human tradition)

Later layers of sacred texts, oftentimes explanatory in nature, are added to the scriptural corpus: Samhitas (Vedas proper), Brahmanas, Aranyakas, and Upanishads (dating from 1000 BCE - 1500 CE)
 

The "caste"-system:
 

"Caste" derives from a Portugese word, casta, meaning: "animal breed, lineage."

Vedic texts speak of four different varna, literally: color.