Born in 1798 to a respected Quaker family in Pennsylvania, Warder Cresson was attracted as an adult to various new Protestant sects, and took an especially keen interest in the Hebrew Bible. In 1844 he set off for the Land of Israel, having secured the position of American consul to Jerusalem, although by the time he arrived he found a letter revoking the appointment. Alan Dowty tells his story:
[In the 1840s Cresson] was drawn increasingly to Judaism, coming into contact with Rabbi Isaac Leeser of Congregation Mikveh Israel in Philadelphia, an important Jewish leader of his time. . . . Like most devout Christians, Cresson read the Old Testament (that is, the Jewish Bible) closely; unlike most, he came to feel that it was definitive and [more authoritative than] the Christian scriptures that came later. [While] Cresson embraced the goal of the Ingathering of the Exiles, he rejected the attendant notion that this required Jews to convert to Christianity. . . .
In March 1848, after nearly four years in Jerusalem, Cresson converted to Judaism and took the name Michael Boaz Israel ben Avraham. Dowty continues:
Cresson returned to Philadelphia in September of the same year, eager to bring his family into [his new faith]. But his wife . . . and most of his family, claiming that Cresson was clearly out of his mind, lodged a charge of lunacy and obtained a verdict of insanity from a sheriff’s jury.
Cresson appealed the verdict and remained unconfined pending trial, which took place two years later, in May 1851. . . . Cresson’s lawyer argued that the basis of the lunacy claim was what would today be called anti-Semitism, [accusing Mrs. Cresson of] “endeavoring to stigmatize the venerable faith of Israel.” In his charge to the jury, the judge instructed them not to take religious beliefs into account in determining whether Cresson was insane. Accordingly, the jury took very little time to declare Cresson sane. The case was widely publicized at the time and the outcome was applauded by most major newspapers. It is considered a landmark in the defense of religious liberty.
Cresson, unsurprisingly, divorced his wife. He quickly returned to Jerusalem, marrying a woman in the Sephardi community and fathering two children (neither survived beyond childhood). . . . In his later years he tried to further pre-Zionist Jewish settlement by building an agricultural colony in the Valley of Refaim, the area later developed as Jerusalem’s German Colony. But it appears that he was never able to raise the necessary funds.