I have received a perceptive comment on the Gods worshiped in the Vedas.
After completing the Shruti texts, I moved onto the Smritis – the Itihaas and the Purans when my daughter, while reading the draft, commented : No portion of the Veds (including the Upanishads) really talk of Brahma, Vishnu, Mahesh, Ganesh, Devi etc. How did the transition take place.?
The Agams do provide a clue but to my mind there are several missing links – especially in the practices as seen from Uttar Pradesh where I come from. Can you throw any light on this?’
I kept the comment pending lest I forget it.
The Vedas as rightly said do not mention the Trinity Brahma , Vishnu And Shiva as much as the other deities as Indra, Varuna , Agni.
Shiva is not mentioned at all, excepting in Sri Rudram as Sivaaya Ca, Sivadharaya ca.
No mention of Brahma either.
But we have references to Vishnu and Narayana.
Example.Narayna Suktham ,Vishnu Suktham.
Devis Lakshmi and Durga are mentioned , Sri Suktham and Durga Suktham.
Vishnu is mentioned six times, in the Rig Veda
Ganapati Upanishad is found in the Atharva Veda.
As to how the Trinity and other deities we worship today came into play is the human necessity of having a fixed an object for realization with specific attributes that are identical with human attributes.
Vedas speak of Para Brahmanas Nirguna, with out Attributes.
Saguna, Gods with attributes were limited to what we now consider as minor deities, like Indra, Varuna and the others.
More of karma kanda was followed and Bhakthi Bhavam the Path of Devotion does not find a place in the Vedas as much as in the post Vedic period.
Vedic karmas were performed as per the Vedic procedure, were more mantra oriented( the deities are bound by the Mantras) and the Deities like Agni were used as conduits in carrying the oblations and these deities were considered to be the benefactor of human needs.
Howver as the number of these deities were numerous, there was a necessity of establishing much more powerful deities, who are are in control of these deities.
Thus were the Gods Brahma and others.
As for as Shiva is concerned there are references to Siva in the South. Pre Sanatana Dharma period where He is described as Adhi Shiva and a First Siddha.
I have published a couple of articles on this and more to follow.
So many of the Gods we worship today were not mentioned in the Vedas.
That does not necessarily mean they are Illusions or lies.
As I have mentioned in my earlier Post that Hinduism does not believe in personal God but understands the Human Mind;s necessity og having one.
So it allows the worship of these deities.
As Krishna says,in The Bhagavad Gita
“I shall grant the boons to one who prays in the Form he worships and in the same manner that Deity would’
Thereby implies the Nirguna Upasna can be supplemented by Saguna worship.
Deities mentioned in the Rig Veda.Numbers indicate the number of times the Gods were mentioned.
- Indra 289
- Agni 218
- Soma 123 (most of them in the Soma Mandala)
- The Asvins 56
- Varuna 46 
- the Maruts 38
- Mitra 28
- Ushas 21
- Vayu (Wind) 12
- Savitr 11
- the Rbhus 11
- Pushan 10
- the Apris 9
- Brhaspati 8
- Surya (Sun) 8
- Dyaus and Prithivi (Heaven and Earth) 6, plus 5.84 dedicated to Earth alone
- Apas (Waters) 6
- Adityas 6
- Vishnu 6
- Brahmanaspati 6
- Rudra 5
- Dadhikras 4
- the Sarasvati River / Sarasvati 3
- Parjanya (Rain) 3
- Vāc (Speech) 2 (mentioned 130 times, deified e.g. in 10.125)
- Vastospati 2
- Vishvakarman 2
- Manyu 2
- Kapinjala (the Heathcock, a form of Indra) 2
Minor deities (one single or no dedicated hymn)
- Manas (Thought), prominent concept, deified in 10.58
- Dakshina (Reward for priests and poets), prominent concept, deified in 10.107
- Jnanam (Knowledge), prominent concept, deified in 10.71
- Purusha (“Cosmic Man” of the Purusha sukta 10.90)
- Apam Napat
I have taken as a frame of reference as it is the oldest and regarded as most authentic.
I belong to Krishna Yajur.