Judaism was to Josephus, as to Philo, not a contrast or antithesis to Greek culture, but the perfection and culmination of culture.
The most curious efforts to propagate Judaism were, however, those which were clothed in a Sibylline disguise.

In heathen antiquity, the Sibyl was an inspired prophetess whose mysterious oracles concerned the destinies of cities and nations.

These oracles enjoyed high esteem among the cultivated Greeks, and, in the second century B.C.E., some Alexandrian Jews made use of them to recommend Judaism to the heathen world.

In the Jewish Sibylline books the religion of Israel is presented as a hope and a threat; a menace to those who refuse to follow the better life, a promise of salvation to those who repent.

About the year 80 C.E., a book of this kind was composed.