John the Baptist

Week 37  Matthew 3

John is called The Baptist because he baptized people.
I was wondering if baptism was a brand new development or if it was an already-known practice.
It’s possible that baptism was one of the things that had developed in the long years between Malachi & Matthew (I do know that a lot of things start showing up – almost like out of thin-air – as soon as I start reading the NT).
Anyway I remember that the books of Moses have instructions & regulations about ceremonial washing. That’s a bit different from John’s baptism – in the NT John actually took people into the Jordan River (where they were maybe submerged in the water).
I checked a word book to find where the OT mentioned baptism. I found baptism & Baptist & baptize & baptized are used in Matthew (never in the OT). Baptizes is used once in John. Baptizing in Matthew 28. None of the words are used in the OT. And I don’t really think the idea is either.
That leaves me with two choices: a) baptism started to be practiced in the long interval between Malachi & Matthew or b) John the Baptist invented baptism as a brand new thing.
Personally I like b) (it’s pretty nice to think of John as the Founder & Originator of Baptism). But I don’t think I can because it’s possible that baptism somehow evolved during The Big Silence between the OT & NT – and that I just don’t know about it.