For the Vedic brahmacarin there was a certain initiation ritual which established a brahmin in the studentship.
How was it for the Buddhist brahmacari? Was it casual, or formalized? How was it for lay followers and monks? Is the Sutta pitaka consistent with the Vinaya?
We find for example a standard formula for the upasaka in the suttas:
Let Master Gotama consider me a lay follower who from today has gone for refuge for life.
Upāsakaṃ maṃ bhavaṃ gotamo dhāretu ajjatagge pāṇupetaṃ saraṇaṃ gata
Do we know how binding that was? etc.
If you have some knowledge or can refer to literature I’d be grateful!
I think they were required to get a tattoo of the Buddha on their lower back!
Taking refuge is an undertaking and there is no contractual obligation or binding.
You can come and go as you wish.
In regard to taking refuge, there are tons of Sutta’s to support this.
However, I can’t remember Buddha giving five precepts, eight and ten etc.
I wonder what happened in Uposata days in Buddha’s time.
If you give it some thought it couldn’t have been too simple to be a Buddhist at that time. Not talking meditation or a tattoo, but for example bhikkhus coming to a village would know after a while where they would get food on a regular basis. How?
Also it was probably a household decision, not just an individual one. Brahmin brahmacarins were also begging food, but just from women, and while there have always been households that gave everyone, ‘turning’ a household from Jain or Brahmin to a Buddhist supporter couldn’t have been a small thing - neighbors would recognize, extended family etc. That’s why I wonder what the ‘official declaration’ was.
And apart from householders: What was the official ritual for becoming a monastic, and do Suttas and Vinaya differ in that respect?
Ordination is covered in the Vinaya, and surely developed into a different structure than it had when it started. The earliest is the phrase, “Come, monastic” after people asked to be taught by the Buddha, for example.
I don’t recall any sutta having any further details beyond the Vinaya.