In ancient days a Yajnam was performed by 16 priests. The main priest was called 'Adhyaryu'. He measured the venue of the Yajnam, made the Yajna fire and did such other work and at the same time chanted Yajur Vedic hymns. Another priest chanted the Sama Vedic hymn called 'Brihath'. Another priest chanted Rig Vedic hymns.

When we read the Rig Veda, we start getting the feeling that even in the initial days of the Rig Veda, the other Vedas were also there. In one of the Sukthams in the early part of the Rig Veda, we see the following, " Indra! Sama Vedis praise you by singing the Samam 'Brihath', Adhyaryus praise you by chanting Yajur Vedic hymns and Rig Vedis praise you by chanting Riks." We also see references to the caste system. It is possible that even when the Aryans were in Iran, they conducted Homams and Yajnams and had a caste based social organization. In other words, the Vedas might have originated in the Aryan society even before they started migrating eastwards.

By the time we read about 100 Sukthams out of the 1017 Sukthams, we come across many things that we are familiar with. Some of these are -
- Many Sukthams refer to Darba grass which is most essential for Vedic ceremonies now also.
- We see references to three worlds
- We see references to Agnihotram and Somayagam in several Sukthams. These are conducted by some people today also. Agnihotram is a Vedic Homam which every married Brahmin is supposed to do everyday in the morning and evening. A US based Indian doctor by name Dr.Deerganghi is doing extensive research on Agnihotram right at this moment.
- We come across names of kings like Pururavas, Nahusha, Yayathi etc. These names have been used in later epics and Puranas like the Mahabharata.
- We come across names of Rishis like Kanvan, Bharadwajan, Viswamitra and Vasista. Suktham 53 of Mandalam 3 refers to a quarrel between Vasishta and Viswamitra. Subsequently in Ramayana, this has been elaborated as a lengthy story.
- Many Sukthams say that rice, milk, curd and ghee are used as 'haviz'(offering to Gods). This practice continues to this day. But the most important haviz in Rig Veda is a mildly alcoholic drink called 'Somam' prepared by crushing a creeper by name Somalatha (botanical name SARCOSTEMA VIMINALIS). All the 114 Sukthams of Mandalam 9 are about Somam. In these Sukthams , Somam itself is treated as a God . The Rishis pray to Somam to make the Gods happy.
- We see references to Satwam, Rajas and Tamas, the three types of human nature. This has been subsequently elaborated in the epics and Puranas. Chapter 14 of Bhagawad Gita deals with these in great detail.
- We see statements like 'dead people go to the Pitrulokam'.In one Suktham a person prays to the Gods to bless him with a son so that the souls of his father, grandfather, and other ancestors will not be thrown out of the Pitrulokam. This belief has continued to this day and appeasing of the souls of ancestors plays a dominant part in the Hindu religion. Vedic ceremonies can be performed only by a male, that too after Upanayanam. Pitru Tharpanam, Sraddham and such ceremonies for appeasing the souls of ancestors can be performed only by a son and not by a daughter.
- In Mandalam 10 Suktham 98, a dead man's soul is brought back from the Pitrulokam by chants addressed to Manas(Mind) and the man comes back to life.