It started as a mystery.

During a lecture in England last December, Jonathan Sarna, America's foremost scholar of American Jewish history, said he did not know the whereabouts of one of American Jewry's most important documents: George Washington's letter to the Hebrew Congregation, in Newport, R.I.

Upon this yellowed piece of 18th-century rag paper is a short but powerful statement from the first president of the United States reassuring one of the original colonial congregations that his nascent government guaranteed religious liberty for all.

"For, happily,"� Washington wrote to the Jews of Newport in 1790, "the Government of the United States, which gives to bigotry no sanction, to persecution no assistance, requires only that they who live under its protection...