They are often called the ''forgotten Jews" of Greater Boston, the families of immigrants who left Central and Eastern Europe beginning in the mid-19th century to create bustling, thriving enclaves near the mouth of the Mystic River.

Their legacy as one of the most vibrant Jewish communities in the United States has never been chronicled, historians say. But that void in Jewish history is expected to change, thanks to an ambitious proposal to transform the crumbling, unused chapel at the Ohabei Shalom cemetery in East Boston into an interactive museum dedicated to the lives, struggles, and successes of the Mystic River Jews. Such a museum would have the added benefit of bringing attention to a historic cemetery, located off a dead-end street, that dates to 1844 and is believed to be the oldest Jewish burial ground in Massachusetts.