Something about the verb "founded" bothers me... mainly because I associate that word with things that men invent. And when you believe in a religion you either believe that it was always there or that it was given to you by a higher power, not that a person invented it. But I'll leave the semantic dispute aside... Judaism began with Abraham's covenant with G-d (out of respect to Jews for whom this is an important issue I'm going to spell it the Orthodox Jewish way and not the way I usually do). The story of Abraham can be found in the Book of Genesis in the Old Testament. As to "when" this occurred, see the answer to the previous question ("Who founded Judaism"?) if you're looking for a calendar year. Another important idea to take away from that answer is that the early Judaism of Abraham is not exactly the same as the Judaism that we know now. The most important Jewish practice we can associate with Abraham is circumcision, the way each successive generation symbolically renews Abraham's covenant. Other elements, like the dietary laws that we now think of when we hear the word "kosher" came several generations later and are not mentioned until subsequent books of the Old Testament, most notably Leviticus.

Around 3300 yrs ago (1300 BC)

The first person to be considered a Jewish person per se was Abraham, who lived around 1810 BCE. Judaism as a religion was formalized at the Revelation at Sinai, when G-d gave the Torah to Moses and pronounced the Ten Commandments in front of around three million people, in the year 1313 BCE.

By the time the Sumo Priests of Great Pyramid (Moses)took decision to abandoned Egypt in looking for an own Nation.