When did ancient "Re-Judaization" begin?

LARRY HURTADO: “Re-Hebraization/Judaization” Among Roman-Era Jews.

In short, the analysis in the CPJ suggests strongly that an increasing expression of Jewish ethnic and religious particularly began much earlier than Collar proposes. Even the increased emphasis on Torah and observing its commandments that she highlights in later Roman Jewish inscriptions is surely reflected already in developments such as the emergence of the Pharisees, a party particularly concerned to promote observance of Torah among Jews.