This led him into conflict with both Christian and rabbinic institutions: his books were placed on the Index Librorum Prohibitorum and several Jewish authorities excommunicated him.

His short autobiography contains many details about his life, but over the past two centuries, documents uncovered in Portugal, Amsterdam, Hamburg, and elsewhere have changed and added much to the picture.

In 1614, they escaped this predicament by leaving Portugal with a significant sum previously collected as tax farmers for Jorge de Mascarenhas.

Gabriel was among the Hamburg group, going by Uriel among his Jewish neighbours and using the alias Adam Romez for outside relations, presumably because he was wanted in Portugal.

The Propositions are extant only as quotes and paraphrases in Shield and Buckler (Hebrew: מגן וצנה), a lengthy rebuttal by Leon of Modena,[7] written in response to religious queries about da Costa posed by the Hamburg Jewish authorities.

[8] The leaders of the Amsterdam Sephardic community, troubled by the arrival of a known heretic,[9] staged a hearing and sanctioned the excommunication previously set in place against da Costa.

Three chapters of this unpublished manuscript were stolen, and formed the target for a traditionalist rebuttal published by Semuel da Silva of Hamburg.

Da Costa believed that this was not an idea deeply rooted in biblical Judaism but rather had been formulated primarily by Pharisaic rabbis and was a late addition to the Jewish principles of faith.

Da Costa was relatively early in arguing before a Jewish readership in favor of the mortality of the soul, and in appealing exclusively to direct reading of the bible.

For example, they asked a Venetian rabbi, Yaakov Ha-Levi, whether da Costa's elderly mother was eligible for a burial plot in the Jewish cemetery.

Seeking reconciliation, he first suffered punishment for his heretical views: he was publicly given 39 lashes at the Portuguese synagogue in Amsterdam, then forced to lie on the floor while the congregation trampled over him.

This ordeal left him both demoralized and thirsty for revenge against the man (a cousin or nephew) who initiated his trial seven years previously and marked the final dramatic point of his autobiography.

Transmitted to print in Latin some decades after his death and only a few pages long, it also expresses rationalistic and skeptical views, including doubts about whether biblical law was divinely sanctioned or whether it was simply written down by Moses.

In his lifetime, Examination inspired not only da Silva's answer, but also Menasseh ben Israel's more lasting De Resurrectione Mortuorum (1636) directed against the "Sadducees",[14] and a listing in the Index of Prohibited Books.

Müller publicized da Costa's excommunication, to make an anachronistic point that some Sephardic Jews of his days were Sadducees.

[18] Pierre Bayle reported the contents of the Exemplar quite fully, to demonstrate among other things that questioning religion without turning to revelation would bring one to miserable faithlessness.

[21][22] Reimarus embraced da Costa's appeal to have legal status based on the Seven Laws of Noah, when he made an analogous argument that Christian states should be at least as tolerant toward modern Deists as ancient Israelites had been.