Here is a something nice about Postel by Matt Goldish,
- A contemporary case was that of Guillaume Postel (ca. 1510-1581), the great French millenarian reformer. Postel's mission was the harmonization of Jewish, Christian and Islamic thought, which would ultimately create a single universal religion under a single universal monarchy (France). Postel was also a prophet, but his astounding erudition and the assumption that he was mad prevented these proclivities from causing his execution at the hands of the church.
Postel's scheme of universal harmony again reflects the patterns which have become familiar by now from Iberian examples (note added - Michael Servetus): it is prophetic, deeply practical and political, and involves a return to primitive Christian Judaism.
Professor Kuntz, Postel's biographer, says that "Postel constantly speaks of the Jewishness of all men. He speaks of Christian-Jews, rather than Jewish Christians, and the distinction is significant." Postel studied Hebrew and Aramaic, and eventually became an actual convert, though he remained a "Christian Jew." Again, then, we have an example of a Christian millenarian who found that a Christian-Jewish space, like that occupied by conversos, was the best possible path toward a true apocalyptic reformation.