What is the origin to the phrase 'in vino veritas'?

It is Latin for 'there is truth in wine '

https://uvamatris.com/en/2020/01/il-proverbio-in-vino-veritas/

The ancient Greeks first said 'Truth in wine.' (I haven't the faintest idea what the Greek is!). The Romans adopted a lot of ideas from Greek civilisation (including communal drunkenness) and adopted the Greek saying translating it to the more-widely known, 'In vino veritas.'

The following website is a source but is not terribly informative other than that.
https://www.merriam-webster.com/dictionary/in%20vino%20veritas

This is attributed to Pliny the Elder (AD 23 -79)
Roman scientist, historian and soldier.
The 'correct' translation: 'Wine brings out the truth' !

https://books.google.com.au/books?id=xJuc416PCFgC&pg=PT178#v=onepage&q&f=false

There seems to have been a similar saying in classical Greece (oinos kai aletheia) which was proverbial by the time that Plato puts it into the mouth of Alcibiades in the “Symposium.” In the early fourth century BC.

Seems to be credited to Pliny The Elder:

Back in AD 77, Pliny The Elder wrote, "In vino, veritas", or "In wine, there is truth."

Pliny the Elder -- Truth comes out in wine.

http://www.brainyquote.com/quotes/keywords/wine.html

http://www.abc.net.au/science/k2/moments/s1147613.htm