Technically Abraham, as he was the one, with whom G-d established the Covenant. Although I'm pretty sure there are lengthy disputes in Talmud arguing that it started with Adam and Hava.
I'm counting from when Yahweh declared Israel his people and handed down the Ten Commandments at Mount Sinai (all mythological, of course, though there may be some real inspiration for Exodus, like the mythological Iliad and the real city of Troy).
The problem with asking "when Judaism started", is that the religion of the Mishnah and Talmud is (very likely) so different from the religion of David and Solomon that they are arguably two different religions, even though one is a descendant of the other.
Possibly, Samaritanism is closer to the religion of the ancient Israelites than contemporary Rabbinic (or even Karaite) Judaism is.
DiogenesKynikos|2 years ago
skissane|2 years ago
Possibly, Samaritanism is closer to the religion of the ancient Israelites than contemporary Rabbinic (or even Karaite) Judaism is.